Teach me videography

Hello I am a photographer and have been doing filming for years and editing but I do not feel that I am very good! I have a Canon 5D Mark 3 and would like to improve my filming skills. Maybe we could go somewhere and try and capture something and you can tell me what I am doing wrong. I might have a trip on 28th May so really need to improve my videography skills before then! Please help. I am based in London and would ideally like to do a few hours this Sunday 19th May. I am negotiable on the price not really sure how much to offer as I want someone who really knows there stuff. Well at least knows more than me. I do know some stuff but I just want my footage to look really professional and to be able to focus and stuff! best setting etc.