If you want to build 2 walls next to each other with Groot, you don’t have to build them one by one, instead you can

As Cloak and Dagger, when in Cloak form, you can actually kill squishy dps players very fast and in a safe way by hitting them

Blocking with Captain America's Shield actually reflects projectiles. The problem is that the reflected projectiles are not very accurate. But you can circumvent this by

After using captain america's ultimate, you can hold block and sprint to knock enemies back. If enemies are close enough together you can push them

If you have a Hawkeye player on your team, you can use his team up ability with black widow to see your enemy’s after images