You might have to give a few more details...
How are you currently shaving? It you are using a 2 or 3 blade razor, the 'lift and cut' action might be compounding your problem.
It could be that a single blade safety razor with a single pass (with the grain of the hair) could significantly reduce your in-grown hair problem.
One tip that I have read that made sense, was to never tweezer the in-grown hair since this will probably cause it to grow back still in-grown... but to rather lift it out of the skin with the tweerzers and then cut the hair with scissors or a razor.
Think of how stupid the average person is, and realize half of them are stupider than that. - George Carlin