Here is my advice. Make sure that you are blocking. Even on a cement surface, blocking will get you much more height on a front flip than just a standard skip. You also need to jump straight up. it'll feel weird because you will be traveling forward with your back perpendicular to the ground instead of angled, but trust me. That should last a very short period of time, then tuck. And don't roll out of the flip man. You should be able to complete the flip with good form, standing up, and then if you want to keep down impact you should roll from there.