I'm new here (and in doing statistics in general).

I have to do a regression analysis on panel data (10 groups, 9 years - 90 observations).

I'm using STATA and i tried performing regression with fixed effect, which showed that basically my model sux.

But what about heteroscedascity and multicolinearity and all this?? Should I perform any tests or anything? I read the theory and I'm trying to understand, but I don't know how to apply it to my problem.

I don't even know how to start..

If somebody has a little time, please help me, I'd be very grateful..