As someone who has suffered for a very long time with ingrowns, I would say take the advice already given to you, but also try to avoid the against the grain pass if you are doing that too. You may also want to check the quality of the lather - not the brand of soap or cream, but that you are working it up correctly. The thicker and more stable the lather is, the better.

If you still have issues after checking all of the tips in this thread so far, I would invest in Art of Shaving's very effective Ingrown Hair night cream. It works a treat!