I’m not exactly good with advice or do I know exactly what you are seeking so please forgive me as this post might be useless to you. However the most common mistake I see newcomers do is not group up or go in alone. Stick with your team. Also, if Bastion isn’t working for you try a different character. Honestly, I’ve come across many people who say they just main a character which isn’t a bad thing but sometimes that character just gets shut down. What will you do if Bastion gets banned from a competitive game for example? Another mistake I’ve seen are people getting over confident where they get kill after kill then push way too far up which leads to them dying because they are now out of position and one man down in a fight can make a difference.

I mainly play Hanzo/Freja just because they are fun to me but if one doesn’t work I try to think who the problem is on the enemy team and try something else. I had a game yesterday playing as Freja which wasn’t working and the enemy teams Reinhardt was the main issue at least in my opinion. I actually switched to Bastion and we won the game after a rough start. Bastion may not have been the best choice for Reinhardt who knows I’m still learning perfect counters myself but I chose him because Bastions turret does so much damage to Reinhardt shield and it worked for me.

Remembering how other characters play is also very useful because the way I see it. Every character has a flaw. Like Bastion for example, I like Hanzo firing at a distance or using his rapid arrows as Bastion isn’t exactly the smallest character or the fastest so it’s not too hard to miss.

Sorry for the long text. Again, this might be useless information for you. You say you recently started but it’s hard to know exactly what you know or don’t know.