need suggestions

I've been working on my bike on my off time.i have the rest of the year off and i have to use my time smart.in my attempts to find an electrical problem i pulled the plugs and noticed that they were a little silverish,the po told me it was jetted...oh well.i pulled the tank off ,just to make things easier to check, cause i wanted to check compression and maybe the valve clearences tomorrow.i dont know what to check first,i need help,can you dudes please give me some input...thanks