I'm starting a deload week this week. Any tips?
Don't half ass the reps. They'll be light, but focus on your technique and force development.
How many reps should I do??
It's not so much the rep range that's important; it's the intensity.
Do the same amount of sets/reps that you would normally do but only use 65-70% of the weight.
Don't go crazy and do a lot of other exercise (cardio, sport, etc.) because you don't feel you have worked-out properly in the gym. A de-load week is supposed to allow your body to recuperate. Enjoy the week and the slight break from training then get back to using 100% weight next week.