i'm a veteran hero zero player , i played with multiple accounts. The first time i played to HZ was in 2015 , on the browser's client

tip #1 ------> upgrade mainly your health , insight and brain! the strength is less important
tip #2 ------> keep donations to a minimum when you are at lower levels
tip #3 --------> spend your money to get better items and skills
tip #4 -------> join maxed teams , they will help you to grow faster
tip #5 -----> partecipate to herocon
tip #6 ------> upgrade your hideout , it will help you a lot
tip #7 ------> do small missions (4-5 mins and few xp)
tip #8 ------> Before u leave the game start a longest mission that you can find. It'll give u lot of exp/money.