Exfoliation is key, but what really works for me is doing it *before* you wax, not after. I started gently exfoliating a day before my wax appointment and it cut down the ingrown hair problem quite a bit.
The other thing is that regular moisturizer isn't enough - you need something with gentle acids like AHA or BHA that keep your skin clear. Some people use body lotion with glycolic acid every night on the areas where you wax, and that makes a difference. Also, tight clothes after waxing make them worse, so those first few days it's better to wear something looser.