Profile of Planet Smasher

One could argue that a Raketenwerfer can come even earlier. Also, the M-42 deals only 80 damage per hit, so it needs 3 hits on a Kübelwagen or 222 and 4 on a 251. It does reload faster than other AT guns, though. I can understand where you're coming from - 2CP would also be alright, I guess.

The DShK should come at 1CP, though. It can be fairly strong, but at 300MP it's also the most expensive HMG in the game, so you can't really spam it.
Both AP abilities cost 15 munitions, but the one the MG42 has is much, much better. It doubles damage (to 8) and multiplies penetration by NINE (19.8/16.2/12.6), while the DShK only gets triple penetration (13.5/9/4.5). It does have higher stock damage (10), but the MG42's rate of fire is twice as high. I would recommend a higher penetration modifier for the DShK's ability, that way it would be more reliable against vehicles without completely obliterating infantry. It could also be locked behind Vet 1 in that case - or the buff to the AP rounds could come at Vet 1 - so that the DShK doesn't completely shut down light vehicles when it comes out.

You want the new OKW MG42 to have the Ostheer MG42 voice? That might not be possible. I'm not sure you can use another faction's voices, i.e. if you give an OKW squad an Ostheer speech code, it might not do anything.

Did you make the normal Ostheer MG42 squad buildable in an OKW truck? The OKW already has an (unused) MG42 squad that you can use, so you'll have the OKW weapon crew and voices out of the box. There might not be any lines specific to the MG42 though. You might also have to fiddle with the loadout/cost a bit, I'm not sure it's the same.

For an Ostheer MG34, I'd recommend cloning the Ostheer MG42 squad and just changing out the MG. You'll have the normal MG42 voices then, but that's probably the closest you're gonna get!

This commander really needs an overhaul. I think tank traps and AI mines should be combined into one ability that comes at 0CP, then they could add something else, maybe Incendiary Artillery - that would fit pretty well. The DshK should come at 1CP and its ability needs a slight buff. The M-42 needs higher penetration, and it could also come at 1CP.
Then you'd have a fairly decent commander that could work well with a T1 build.

OKW often means Volks spam at the moment. They will wreck your armor pretty quickly with Schrecks, so I would advise you to go for an infantry-heavy strategy. This is also good because OKW doesn't have a stock MG, their only non-doctrinal suppression platform is the Flak HT, which is not great.
Against Ostheer, it's a little different, they're less spammy, but LMG Grens are still good and they have some of the best support weapons. But that also makes them a fairly static faction, so indirect fire can be pretty strong against them.

Here's a very, very basic (and fairly safe) build order that has often worked pretty well for me. I don't play on a high level at all, though, so this is certainly not the holy grail of Soviet strategies

Build T2 right at the beginning. Get a squad of Cons first, then a Maxim. Send those straight to the fuel point you want to focus on while your Engineers start capping in front of your base. Get 2-3 more Cons, another Maxim and a mortar, in an order of your choice. Research Molotovs after that, AT nades if you expect light vehicles.

Lock down important points with your Maxims, they are especially strong in buildings. If there are no good ones nearby, you can also build sandbags for them with your Cons. Your Maxims will be your main weapon against infantry blobs, but they can also hold their own against an MG42. Keep your mortar close to hit suppressed infantry. When you have munitions to spare, lay mines where you think vehicles (or blobs) might attack. Always hold back some munitions for a Molotov or AT grenade, though.

Support Conscript pushes with your mortar by smoking MGs and defensive positions. Don't blob your Cons, otherwise one MG42 (or even MG34) can suppress them all. Attack from multiple directions, use Oorah and Molotovs to flank and kill MG crews. Against Grens and Volks, you will have the upper hand at medium to close range with equal numbers. Try to avoid unfavorable engagements, but don't retreat unless you really have to. You can also give your engineers a flamethrower to make them useful in combat, especially against garrisoned buildings.

You will need some real AT soon. I like to build T3 as early as possible and get an SU-76. Use it like a more mobile AT gun, not like a tank. It has good range and penetration, but won't hurt infantry and can't take many hits. Therefore it's important that you always have your infantry in front of them to protect from Schrecks. The free barrage ability is good against suppressed blobs or support weapons. I often get up to three: This will give you enough AT to hold off Axis mediums, even a Panther, and you can heavily barrage Ost support weapons, OKW blobs (when they're suppressed) or even trucks.
If you're behind on fuel, get a ZiS gun before T3.

After that, get whatever you think is appropriate for the situation. Soviet T4 is not great, so this heavily depends on your chosen commander.
Lend-Lease fits this build pretty well: The PPSh will give your Cons more firepower at close range and you can repair your vehicles quickly. The M4C Sherman is decent and allows you to skip T4, if you want. You might struggle if heavy tanks come out, though. The Assault Guards are not great. The DshK is decent, but 2CP is fairly late for an MG.
Shock Rifle Frontline is obviously good for aggressive play. If you get Shock Troops, use their smoke nades (and smoke from your mortar) to get close and destroy his infantry. You can use incendiary artillery to force his support weapons to pack up. The IS-2 is not that great, but a good option if you struggle with enemy heavy tanks.
Guard Motor coordination is just an all-around good commander. Guards Infantry is great at long range (with LMGs ofc), and the heavy mortar is still pretty strong. The T-34/85 is better than the M4C, if you ask me, but you need to build T4. It doesn't need CPs though, so it might still come earlier. You also have the option to go for a Katyusha if you struggle with infantry blobs or support weapons.

I hope this helps a little. You can also watch some replays to see what the top players build. And there's a mentoring program here that might also be an option:
http://www.coh2.org/forum/69/mentoring

I'm not a very good player, but here's some very basic stuff to get you started:

Rush for important points/buildings first, to deny them to the enemy. You can cap the points in front of your base a little later. You also absolutely need to hold at least one fuel point, this should be your first priority. It's good to secure that with an MG. For capping points early on, you can queue move/cap orders with Shift + Right-click, to make it less micro-intensive. Building sandbags with your Cons while capping is also useful.

Don't attack an MG42 from one direction. Spread out your Cons and attack from multiple directions. If it's in a building, use a Molotov.

You floated too many resources before building T2. Getting it earlier would have helped a lot: A mortar is great against MGs and Maxims can also be very strong, especially in buildings.

Don't spam the AT gun barrage, especially if you don't know whether you're gonna hit anything. Use your munitions for Molotovs, AT grenades, Oorah and mines instead.

You should get a T70 if you have a fuel advantage (which you didn't), and it also needs to come as early as possible. Don't rush it forward if you have no idea what enemy units are waiting there.
The SU-76 is usually a much safer choice, it has good long-range AT and a free artillery barrage.

Your enemy blobbed his infantry. Do not attack the blob with one or two Con squads, that's never gonna work out and will only cost you MP. Use MGs instead, they will suppress blobbed infantry very quickly.

If you know that a mortar is bombarding your MG, move it somewhere else. Also, he had two mortar HTs (which is a big investment), and you didn't really try to take them out.

Generally, too many units stood around in your base doing nothing for too long. Microing so many squads can be hard, but that will become better in time. Use control groups if you're not already doing that.

Getting a KV-8 worked pretty well, but it was risky, because your enemy could've had a Panzer IV or StuG already which it would have lost against. All in all, the match wasn't going great, but you could have won, so you really didn't need to surrender.

Sorry if this seems a little harsh, I just tried to point out all the major mistakes I could make out. I don't think you did that bad for someone who just started out!

Edit: Oops, didn't see someone else already is already helping you out. Sorry about that. You should probably listen to CadianGuardsman instead of me