I also have great difficulty with this. I have tried keeping a mood dairy, tracking it with apps and other. But it just doesn't feel right. I also have poor insight. My GF also told me not to analyse it everyday but just to take everything as it comes.

It is hard as I am someone who wants to know what is going on and why. Classic black and white thinker - no greys I am often scared that I miss something because my episodes begin so subtle (both mania and depression) and then suddenly without warning its upon me and i'm in trouble. There is a quote in prozac nation describing in perfectly “...if you ask anyone in the throes of depression how he got there, to pin down the turning point, he'll never know. There is a classic moment in The Sun Also Rises when someone asks Mike Campbell how he went bankrupt, and all he can say in response is, 'Gradually and then suddenly'.When someone asks how I lost my mind, that is all I can say too."

What works for me is to identify certain behaviours with my family and partner. It helps to get an outside opinion. So if I start exhibiting those I know it may be the start of something and I can direct it in another way or see my doctor to adjust my meds. But thats just me..