You can change your physical size by eating the right amount of protein and pumping iron (you probably know this already, easy to say, not necessarily easy to do).
Ironically if you get hench then close fitting clothes will show your physique and any strength or power that may infer.
Make eye contact, speak firmly and assertively and don't punctuate your speech with "like", "um", "erm" and all other number of "vias".
Sort your posture out if you need to and get some solid, decent boots.
There is a proverb that says:
"Fear makes the wolf look bigger"
If you're going to be the wolf you need to be the fear too.
All that stuff to one side, I hope you're okay brother and remember the biggest thing that you need is a heart, you can have a huge heart and be loved for the good you do. Grow taller in different ways.
Love to you my brother.
DBD