How to prolong good spells?

I know we all have bad times; that's definitive of depression, and is what often draws us here, for solidarity and reassurance.

I was diagnosed with moderate depression a little more than a week ago (yay, after 14 years of being afraid to see a therapist, I haz a diagnosis!), which I guess means my good, neutral, and bad days come in about equal measure. I've been feeling pretty good the past couple days, for the first time in a month or so, and would like to make it last. So, do you guys have any (non-drug) tips for fighting off the bad spells and making the good spells last longer?

Thanks!