Double check all the connections on the starter and check the connection on the battery. Make sure that you used the right amount of shims for the starter.
Check if your starter engine gets power when you turn the key. If it does, but does not crank the engine, maybe your starter engine is dead or your pistons have seized. If the starter does not get power, check your fuses and the wiring.
First, make sure that you have good contacts to your battery, that the wires going into the contacts are clean. If you car will not crank then next you should check the starter. I would search on the web for the different tricks for getting a failed starter going. After that, try the alternator.
No cranking can be caused by a dead battery, fouled plugs or wires, lack of fuel due to a clogged fuel filter, distributor, and/or the coil. These are part of the basic tuneup and by process of elimination, the problem can be corrected. Also check the fuses.
Check to make sure your ignitions switch is good by the voltage at the appropriate connector on the column. The make sure the neutral safety switch hasn't failed. Then make sure the starter itself is getting power and that all ground connections are good. Finally make sure the starter itself still functions.