How to win in SpeedHack/LudumDare competitions
Here I finally give away some of the secrets making me so successful in those competitions.
There is no need to prepare, and it also would be against the spirit. E.g. LudumDare is 48 hours, so only that time should be used for the contest.
This is the key trick: Don't. For example, in LudumDare, there are 48 hours of time. Now, if you sleep twice for 8 hours, this leaves you only about 30 hours of coding. So at the most, sleep only once for a few hours, so you get about 40 hours of coding time. But best is to wake up just when it starts, work for 48 hours, then fall asleep again. Good time management simply is what wins such competitions.
The right food is important. You cannot code well with an empty stomach - and you cannot code without lots and lots and lots of caffeine. The best practice is lots of sugared and carbonated drinks, best with a lot of caffeine in them (Coke, Pepsi, Red Bull...). And also coffee. Lots thereof. Then pile up some pounds of snacks near your computer, ready to grab whenever you feel like it. That will give you a good advantage, and the caffeine also will cause you to never feel tired despite the lack of sleep. See how everything here works together if done right?
Creating the game
Now, the main part, how to create your game. Be sure to not start late. Best is to refresh the website announcing the theme twice per second when the start time gets close - you never know if the clock might be slightly desynchronized. Then in the moment you know the theme, start coding.
Don't think about a theme, you won't have a great idea anyway. Just jump into the code immediately. Then after you hacked together something, draw some graphics, make some sound effects, and create music.
There is no time for a clean design, or structured code, or even things like debugging. Just put everything into one file, and only ever add new code to the end. If something doesn't work, dont waste time looking for the cause, but add quick workarounds instead. Your end product is supposed to be a hack entry, no need to have presentable code.
When the dealine approaches, try to add in some gameplay of sorts into all the huge mess which has amalgamated by now. Gameplay always can win you some bonus votes later on if you manage to implement it.
Now, good luck, and also read Sol_HSA's LD survival guide
for a way how to not get anything done all weekend instead!