Here's what the past 3 LDs have been like for me.
Before the theme is announced :
1. Wake up late
2. Do as little work as possible (no computer work)
When/after the theme is announced :
1. Check what the theme is. Have literally 1000 ideas and no ideas at the same time.
2. Work it out on paper.
3. Get an idea that seems good. Start working on it.
4. Realize the idea is shit. A day has gone by, so.. wth, keep going with it.
5. Release a shit game, but better in some ways, than the ones I did before.
6. Realize it was a good learning experience, even though the game was shit.
After the compo :
1. Play other people's games. Realize what could have been done with that theme.
2. Stream and hang out with people. (one of the best parts of LD for me).
3. Watch people playing my game (another one of the best parts of LD).
This is exactly my experience of Ludum Dare. I think I need to play more indie games though. I've been playing nothing but Dota, hearthstone, and AAA games, and it's really hard for me to think of ideas. All of my Ludum Dares so far except one (so that means 3/4) have been about dodging obstacles. Seeing as Ludum Dare is really the only time I try coding, I really have to think of something more inventive.