While most of the discussions on this forum revolve around different medications and manic/depressive episodes. I think that many additional techniques really help dealing with bipolar disorder. In short, having an overall awareness of what is going on in your mind and how this controls your percieved reality is extremely important when dealing with BP.
For instance, I think a very useful way to gain insight on your condition is to keep a journal. Really, you can write anything and it doesn't have to be explicitly about how you feel. Usually, I tend not to focus on bipolar disorder when I'm feeling well, forget to write when manic, and really pour down ink during depression. The overall point is, you can really get a better perspective on yourself and see if and how your psyche changes while cycling. While you may not recognize your own positive words when feeling depressed, it will reinforce that things can better no matter how much you believe it's impossible.
Now after a few cycles of mania and depression, I can obviously recognize how I'm feeling and have been in the past without a journal to remind me. However, writing things down can also allow you to get more quantitative estimates on the durations of effectiveness, and problems with different medications.
While this is not being suggested as a solution for BP disorder, its very important to accurately capture how you are changing over time. Most people with this condition go through similar emotional and mental cycles again and again. That is one of the most frustrating aspects of BP, wondering when you will change.
Reinforcement from others with this condition is useful as it makes things seem like your not the only one suffering. Though providing empathy, others cannot possible assess your situation as accurately as you can through your own words. No one else knows precisely how you're feeling and with a little effort you can recognize the cycle more clearly, and make adjustments to more effectively keep your condition from tearing up life over and over.
I'm not saying that knowing how you get depressed or manic will make you feel any better about your current mindstate. It can give you hope though during prolonged depressions and knowing when to really put on the brakes before hurting yourself or others during mania.
Either way, don't give up, it's almost impossible to succeed by quitting.