First of all, I found that ladder play is most effective when accomplished in series, meaning ideally at least 10 games per day. This way, I reinforce what I'm learning since I'm constantly gaming, so timing and build orders stick to me a lot more concisely. Thus, for those who are using Iccup for the sole purpose of training to get better, I'd say dedicate at the very least about 7 games or 3-4 hours a day.
The next thing that I found important was paying particular attention to the games I lost or had immense trouble with. Watching your own replays here are a great way to learn; however, there's a right and a wrong way to watch replays. To expand, I'll list some things I've kept in check while repping.
-Watching replays within 24 hours helped me most since I could remember what had happened.
-I focused mainly on what my opponent did since I already know the builds and strategies I've used in that game.
*-Watch additional replays by better players to analyze which builds are best for that particular map/matchup and why.
*There is a HUGE difference in learning when you're casually downloading replays to get better and when you're actually applying what you know from mass games while watching downloaded replays.
So far, this is what I've been doing, and it's been working pretty well. The biggest benefactor to mass gaming is that literally EVERY supplementary material you use, such as strategy guides and dl'ed replays become SO much clearer. So basically, in the end, it's going to end up the same way as with everything else - you practice or you don't get better.