I have mostly recovered from a nasty bout of PCS that started over 3.5 years ago. Life is now humming along (in fact it is better than before my injury), but getting to this point was by no means easy.

Here are the things that I believe helped me the most:

Rest
Time
Keeping stress low (as best possible)
Good nutrition w/ varied diet including sufficient protein
High-quality fish oil supplement, vitamin D3, good-quality multivitamin
Being disciplined about limiting cognitive and physical activity (not overdoing it) and shutting it down and resting when necessary
Very gradually increasing activity (as slow as necessary - over months/years if necessary)
Support from loved ones who get it (these may be few in number)
Learning relaxation techniques (might be a slow walk in natural/quiet surroundings, a breathing/relaxation tape, classical music, hot bath, etc.)
Understanding that recovery can take a long time
Perhaps most important: no further head impacts! Daily reminders/mental cues can help with this
Apart from learning from others' experiences, don't compare yourself with them - each head injury is different
Acceptance that you've had a serious, life-changing injury

For most people, it does get better, but recovery can take quite a while. Be good to yourself. Recovery is a marathon, not a sprint - it's a cliche, but one that is profoundly true.

My best to you (as Mark likes to say).