The first one, never listen to others. The can try to maipulate you in the direction of their own investments. Be careful for this. Next, stay in safe side, don't exceed extreme volumes while trading.
That are general and necessary rules!
I would like to add some. Don't rush for buying any coin based on your inner wisdom and the ones shown quick jumps. I have seen many people buying coins just because coin jumped 2-3x in a day. But jump shows already achieved potential. Buying at pumps will only give you losses.