For the past quite-a-few weeks, I've been using this productivity method, where I write out things to accomplish each week and highlight them when they're done, as well as finding successes/good things/goals/things to look forwards to for each week. It's been working really really well, and in a counselling session I went to earlier this week the counsellor felt it's probably not a coincidence that my mood's been a lot better roughly since I started doing that. However, there are some days when it doesn't work- for example, when I'm feeling low or unproductive or tired, and everything seems a bit impossible and too much effort. I thought about this, and came up with a fairly simple solution- breaking everything right right down. This means that I do small things, then get to tick them off, and that spurs me on to get more stuff done, and I end up getting things done and feeling accomplished, which improves my mood a lot!
To explain it a bit more- today I wanted to tidy my room, but really didn't feel like it, resulting in spending half an hour organising my incense sticks instead. So, I looked at my to-do list and broke it into really tiny things, such as 'take recycling out', 'sort out CDs/DVDs', 'put clothes away' and 'take stuff down to revision'. It meant that the tidying didn't feel like a mammoth, time-consuming, impossible task- I got it done easily, and felt accomplished every time I got to tick something off! It works!