yea thats pretty broad, but i guess ill throw out some ideas to help you.
first, click the aperature down on the enlarger a few ticks- lets you have a longer exposure time so you cantroll it better. i would also reccomend using a filter on most pictures (higher the filter number, the more contrasty it will be). dont let any light get in contact with the paper or else it will expose the paper and it looks shitty. even if somebody leaves the bag of paper open, take the paper from the bottom because some light probably leaked into the bag.
let the pictures develop with constant agitation when in the developer, fixer, etc... and dont let them get stuck to eachother.
you may also need to burn/dodge (darken/lighten) images, and you will soon learn a bunch of ways you can do that. when you do though, make sure to move the object your using to dodge/burn so it is not noticable where you did it (if you dont, there will be a line where one side is more exposed, and the other side is less exposed, if that makes sense).
one last thing, that i dont like when people mess up, is to get the boarders on the paper right. make sure its set correctly in the little tray or w/e your using to hold the paper and it will look a lot more professional when the picture is done!
also on test prints, i find its helpful to write on the back in a pen the exposure time, filter, and any other information that will effect the photo, so that if you come back to it the next day/week/whenever, you have all the info right there!
if you post what your pics looked like, it will be easier to give more relavent advice though! good luck with your pictures, i love making darkroom prints.