Please help me time my engine...

I own a 1988 Honda Accord lx; 2.0 sohc, carb, 5spd,... that cranks but doesn't start. I've ruled out everything but the mechanical and ignition timing. I've never adjusted the timing, and I can't afford a mechanic;
Can anyone please walk me through both how to set the mechanical and ignition timing for my engine?

Thank You.

I am sorry but ignition timing, as in setting with a timing light, doesn't just change by itself. Your distributor can move clockwise or counterclockwise by loosening the distributor mounting bolts and twist the distributor so that the timing marks line up using a timing light. But... unless your distributor came loose your timing shouldn't have changed and need to be set. More than likely something else is wrong not letting you engine to run.

Can't the timing belt slip a notch? If so, how would I reset it?

Yes the timing belt can be off. you can check it by bringing cylinder #1 to TDC on the compression stroke. Using the timing marks on the flywheel. then with the timing belt upper cover removed (you have to take the valve cover off) check the timing marks on the cam gear.

if the belt is off, marks don't line up, I would recommend replacing the belt and the water pump while you are there. It's a big job. about four hours for a "B" level mechanic. and you have to make sure you get the correct tension on the belt when you are done. Be careful if you haven't done it before. mistakes could be costly.