I've always hated tips on startup, which are boring and pretty useless.
But, what about popping up tips at the right moment, right when they are needed (and prior a noob starts makin' mistakes)? This is an effective way to avoid redundant answers on the forum.
I suggest some gotchas to tackle:
a) When start a first time compiling, explain slowliness
b) When someone use a custom layout class, u++ should remember him to put class declaration before layout include
c) Vector<int> a,b;
b.Add(5)
a = b;
remember: [Beware! You are about to 'castrate' b!]
I like U++, but it must start to really help the noobs (which in the long term is always a good investment)