How to hit a badminton ball harder and higher?

Im not into sports but i want to try badminton for a change. How am i supposed to train myself into hitting the ball harder? I wanted to go for a tryout but im too scared bcoz i may just be ashamed of doing short hits or i may compare my hits with the other players cause i hit it very weak. Do i have to do some grip trainings other than training badminton with someone?