Retreat early when being attacked by several units at medium range. Don't wait until your shield is 0-25%, otherwise those enemy units attacking you at medium range will continue to attack you as you move into long range, which is something you want to avoid with such a low shield. If you're being attacked by a machine gun and a sniper at medium range then you'll probably want to retreat at all shield/health levels.
Only retreat as long as someone is attacking.
Don't retreat because your shield is low, but because someone attacks you. If no one attacks you anymore stop the retreat process.
Minimize the time spend switching attack targets.
Usually a bot should continuously attack the bot it started to attack. (by filtering a target attacked in the previous tick) Create strict rules for when to switch targets. For the sniper and machine gun, whose reload time is quite long, it's especially important.
Prioritize enemies that are already being attacked by your allies. Also prioritize enemies with 0-25% shield.
Focus the enemy sniper.
Pay a lot of attention to your opponent's sniper. Your sniper should prioritize attacking the enemies sniper. If your sniper hits the opponent's sniper then it's probably worth changing the attack target of all your nearby units to it, even if they are attacking medium range units. (and only if it is safe/worthwhile doing so)
Shoot medium range.
Aggressively push to medium range. Little damage is done at long range, so pushing to medium maximizes your damage and also pushes your opponent, especially if you have many pushing at once. Careful, a bad push can be a big risk too.
Push in the right moment.
Don't push when being attacked. Sometimes the pushing process should be aborted, because too many enemies are around.
Flank or circle bots.
Flanked and circled bots get easily destroyed. For flanking moves one can use an APS (use a combination of moving to and fleeing from bases, resources and bots to navigate).
Mid game scoring has pros and cons. Scoring to much leaves you defenseless against an aggressively pushing enemy. Scoring not at all will probably result in a game lost 0:1. Keep an eye on the health values of your bots and if the enemy team is scoring.
Try to rush for early resources or smuggle resources mid game. Sometimes also picking 2 or 3 resources at once works.
Shoot at second sight
The shotgun should not always start shooting at the first bot it sees at medium range. Its good to get as close as you can to medium range units, especially if they are retreating or being attacked by an ally. This will give your shotgun more medium range shots as the enemy unit tries to escape from medium range. For example only stop moving towards medium range units when at least 2 units are in medium range.
Decorator for Meeting Point that starts to score if there are only 4 bots left.
Think about maintainability.
Don't use to complicated structures, map and bot specific stuff. It's easier to make one generic AI then to handle a truckload of specialized ones.
Decorate a generic AI.
The decorator pattern can be used to add flexibility to a generic AI. A decorator is a simple program to tell a bot what to do at the start of the map or in certain situations. Tags or conditions can activate or deactivate certain parts of the generic main AI. The different parts of the main AI are included as a sub AI.
New players can totally ignore tagging. (especially for combat)
Don't follow rules. Sometimes you have to break a rule to dominate. Some rules also have cons one should be wary about.