For beginners who die a lot.

1. Take it easy. It's a speedrun, but if there is somewhere you always die at, take care. A few seconds slower is always better than up to a minute lost due to death.
2. Use secrets to your advantage. They may not be the quickest way to perfectly speedrun that particular level, it will solve difficulties and death is worse than a couple of seconds in delay.
3. Use certain bonus blocks and similar to get past some tricky jumps where a trampoline or similar may otherwise be necessary.
4. Pickup powerups occasionally to assist a part otherwise difficult. This is allowed.

This should shave a couple of minutes off your time!

(...hopefully :D)