Marines In Space?

So I mentioned earlier in this blog that I play Space Marines..and I am completely clueless when it comes to painting them. Someone needs to help me wether it be pictures or in person(North Jersey only!). I have problems finding highlights for my Imperial Fists color scheme. I use Sunburst and Golden Yellow, but the Golden Yellow seems to be a color that looks better if it was a base coat but it does not cover well. TIPS.ADVICE.help?