Multicollinearity / Heteroskedasticity / Serial Correlation

Hi all,

So I understand what each represents. But what trips me up is when they show a chart, and it shows individual somg lags and autocorrelations… what am I looking for to see if there is serial correlation… heteroskedasticity, or multicollinearity? For example I completely understand that multiC is when there is a high correlation between the independents… but what would that show in a model? This just frustrates me, thanks guys

negative serial auto correlations–look for pattern: +,-,+,-

Multi coll-- look for high correlation btwn independents