When naming variables, use names that make sense and be consistent. For example, you might always want to use lowercase and substitute underscores for spaces to get easy_to_remember_variables.
Always put a semicolon at the end of each line, even if your code works without it.
Every time you work on your code, take some extra time to add some comments and tidy things up.
If you're stuck, take a break.
When recycling someone else's code, the best shortcut is to take the time to really understand how it's working.
Hello World!!!