It exists a lot of methods you could find on the internet or in some books to make the process a lot easier. I would say the most important is you feel confortable with your way of doing things.
For example, if I have to put my idea on a paper and study all the parts of a project before starting coding (the way I learned at school), I knew a genius guy able to write immediately and with less debugging then I am doing.
I would say :
- write down your idea describing what the app needs, does and produces
- try to identify what you know and what you have to learn
- if any learn and prototype those parts
- identify if you have reusable part of your app
- use the less "hard coded variable values" and use variable content the more often you could
- while coding write down (as a comment in the code itself or on paper) a description and any information you would need in the future about what a sub, a variable, etc does (when it is not obvious of course)
- code the app
- take some rest
- debug
- create scenarios to check the way the app works and make the receipt
- even when the app works, be ready to come back to make corrections (because we don't know all and all make errors)
Good luck