Once all the caps are in the board, stop and double-check everything. For every new cap you installed:
Is the orientation correct?
Is the value correct for that position? Compare the kit's list (if you have one) with the manual's. Sometimes the kits have errors.
Is the orientation correct? Yes, check it again. You *really* don't want any put in backwards.
If everything looks good, solder them all in.
Then, trim the excess lead sticking out the bottom of the PCB. While you do that, make sure you didn't miss any when you were soldering.