Before how to shoot.. Although it sounds simple, keep in mind that you are controlling a character who moves in a similar way to a tank. It's difficult to move, shoot, aim, and sanitize on a mobile device. The situation becomes even more challenging when all the zones are closed and you have only a few players left. Brave Frontier Tier List
You should run away and get as much healing as possible.
It's a good idea at any stage of the game. However, it's crucial to keep an edge near the end. There is a high chance that other players can hear you if this happens. If you are unable to get a quick kill in 1v1, it is important that you disengage quickly. Otherwise, anyone watching you will be able to aim if they stand still. You can.
Keep your energy up and your body healthy. This will allow you to speed up your recovery and help with those last-ditch battles.
Use your vehicle only at the beginning. These vehicles are easy to use, and if your vehicle lands in remote areas, you will need something to hoof it in those areas that close and when there are many bridges. The engine noise is not worth it, especially if you have a smaller map to navigate. You can be a sneaky ninja.
Shoot to kill. Spray and pray works best in mobile firefights. Shoot only when you need to. Gunfire attracts attention just as much to you as engine noise, so don't let anyone else take advantage of this distraction.