Bipolar disorder is generally recognized as something of a slippery customer when it comes to diagnosis. It certainly isn't something you can diagnose yourself and in some cases it can be a case of waiting to see if treatment for the condition makes the person feel better (thus confirming an initial diagnosis).

There are, of course, many things that help to point to a possible diagnosis. It is worth reading this on the causes of bipolar, and this in terms of your own risk factors. You could also try this symptom checker which will help to focus on the specific issues you are interested in. As to the business of diagnosis, try this article, as it mentions conditions that mimic bipolar as well as some of the specific tests that may be used in helping to form a diagnosis