This is a 'team brawler' what that means is you win or loose by how well you work together as a team. You can have RTZ level micro but if you ignore what your team is doing you are going to do more harm than good. All as one or not at all.

Here are some general guidelines for how to play an average map.

Lane stage: from lv1- to about lv 7 or 10 you should always be in lane soaking xp. It is okay to trade some blows with the enemies but you should never really commit to anything since in the early game kills are really not worth much xp. Just play defensive and keep you mana/hp pool healthy and ready for the first objective. If you die at all before the first objective that is a mistake that should not have happened.

The only exception to what I described above (lane soaking) is when an objective comes up on the map. Here your team needs to decide if everyone is committing to the objective or if your going to continue to push/soak lanes for an xp lead. Usually in the lower mmr range it is always a good idea to make a beeline strait for the objective and assume everyone else on your team is doing the same. If your the only one not helping at the objective your team will get wiped (4v5) and its a huge net loss.

***If the enemy's team is lv 10 and your team is not level 10 DO NOT FIGHT. Even if it means giving up an objective. You will loose the fight and still give up the objective.

Post laning stage: after lv 10 there is really never a reason to not stick together as a death ball. Yes there are some heroes that can effectively split push, but as a new player you will probably just end up getting ganked and again putting your team in a 4v5 scenario. This game at its core is a game of two deathballs fighting over objectives. The team with better coordination usually wins.

I cannot emphasize this enough. This isn't dota or Lol were the carry player can do his own thing while the other 4 heroes do team fights. Heroes of the storm forces teamfights with the objective system. If your team has less heroes than the opponent at the objective you will loose every time.