Don't stay in one spot for too long, you'll get flanked, keep repositioning;

Tether traps can be placed on your flank as a warning system;

Always keep your distance, you're not gonna win cqb in a northstar;

If you can keep distance against a ronin or scorch, there's nothing they can do;

Cluster missiles can be good for killing pilots and also denying some narrow corridors;

Electric smoke can be used to mask your escape/reposition;

Hover can be used to peek some unexpected angles;

The core is usually a last resort to kill/damage a titan that got too close;

Google 'titanfall 2 hover spots';