Check the shoutcasts subforum to find casters (like myself, actually). You can send them a PM to ask them to cast your game. Almost all casters prefer games that are less than 45 mins though.
If you just want some tips in the comments section, then you can say so in the replay description.
Also, if your game demonstrates a certain facet of the game that merits full discussion (Scavenge Doctrine is OP! etc) then you should create a new forum topic and link your replay there.
For the ladder signature, you can see instructions here:
http://www.coh2.org/topic/552/coh2.org-new-featuresfixes/page/5#post_id189534