what is the one mistake that beginners always do that i should avoid?

hyoshawn

One of my friends who is a guy 5ft 7in and roughly 150lb wants to start working out, and his goal is to get big or increase his muscle mass. He just started working out, and im trying to help him but... I have been working out for 5 years now it's been so long since i have started i don't really remember how i actually started, and what mistakes i made. Any advice would really be appreciated thank you!

kaizaku

Correct form, that is one of many mistakes beginners make.

kommodevaran

For more and more detailed answers, post in Fitness and Exercise