There are many facets of arm wrestling and for me it took a long time to figure out what works the best for myself to get to the point where I can slow down a match to learn what is happening
I don’t know if you can pick just 1 with out another . Hand control is huge but you need either good back pressure or side pressure to go with it . A good hand, with lacking side and back pressure is also not going to get you far . You need 2 of these 3 together to make a splash.