My two cents on what is a prayer and how to create a good one. Ask for something. See the six keys to SFQ for elements I think will make it a good prayer.
As for fasting, there are many different types. Fasting is stopping. Fasting can be not eating chocolate, or it can be not eating of drinking anything, it could even mean not doing something. How much you will stop and how long you will fast for is a very personal thing. Always remember to be safe and healthy.
I wouldn't go out and try and force myself to sprint (sub 5 minute miles) for 26 miles today, but some people can. A similar idea can apply to fasting.
Another good bit of advice given to me about fasting is to decide what you fast will be (How much and how long), being reasonable and safe, then commit to it's start and see it through. This by itself will help your development.
Meditation when the body is more quiet, as during a fast, can be rewarding.
Wishing you good physical, mental, and spiritual development. Balance and flow.
You are perfection.
Iam2 
