That's a really good question. We can pray about many different topics. 1 John 5:14 states: “No matter what it is that we ask according to [God’s] will, he hears us.” Some things we can pray about are: Faith in God; holy spirit, or God’s active force, to help you do what is right; strength to deal with troubles and to resist temptation; inner peace or calmness; wisdom to make good decisions; help with daily needs; and forgiveness of sins. I hope this helps.
You can pray about anything. It isn't about asking God for things. It is about talking with our heavenly father. It is part of building our relationship with him. The hard part isn't how do we talk to him because he already knows our hearts and minds. The trick to prayer is learning to listen to what he tells us.
You can pray about anything! Im catholic, and i think our prayers are all awesome, and good to say in a pinch. but the times that im closest to God is when i just talk :) we just have a conversation, like two old friends ^_^
We can pray about pretty much anything - with the exception of things that violate Gods word. God isnt likely to like it if you pray for something mean or violent. And its highly unlikely He'll even listen if you ask for things that violate the bible or would hurt yourself or someone else. Most other things you could ask for but He may or may not answer depending on the purpose of the request and the effect it will have on others, etc. Basically you can pray for almost anything but Gods answer may be a resounding 'no' to some requests.