Unless you’re testing the water to see if you like DJing with software, I’d recommend avoiding a laptop-only setup if possible. You really can’t replace the tactile feel of controlling the music with a physical piece of kit (controller/CD decks/turntables – whatever your poison), it’s awesome!
Also (as much as I wish this wasn’t the case), a laptop-only setup tends to give people the impression that it’s somehow easier or you’re not professional. This is utter nonsense obviously as it can be harder to DJ only on a laptop (as you’re probably finding no doubt).
Having said that, if the laptop is literally your only option, you can get keyboard overlays (little stickers for your keys) which provide a colour-coded, more visual way of controlling the software for most major programs (Serato/Traktor etc).
I hope that helps!
GP