Controlling Approach is like baking a cake, it’s all about building up the altitude layers to give you ease of mind. The number one rule of radar, never break separation.
6.2.1 — Terrain separation: aircraft must be provided with at least 1000ft AGL (above ground level) terrain clearance at all times.
6.2.2 — Aircraft separation: aircraft must be no closer than 3nm laterally or 1000ft vertically at all times (see 220.127.116.11 below).
The entire training curriculum for Radar is centered around those two rules. Use vertical separation to your advantage, it is your best friend.
Have a plan. Stick to the plan. Be ready to adjust the plan. Be sure you’re ready to adjust the plan because you likely will have to. Keep it simple.
Create scenarios that will be predictable. If you have a good plan, you’d be able to close your eyes for 30 seconds and know where every aircraft is on the radar when you open them.
Be consistent. Consistent headings and altitude assignments go a long way. It’s the first thing I’d teach any new radar controller. If you’re consistent you’ll have a lower likelihood of becoming surprised and will have more time to worry about other things.
Don’t panic. It’s wasted energy.
Try to get in a rhythm. Once you have the plan and have executed it, you’ll find it easier to scan the field and get in a rhythm. Check here, then check here, then check here, clear an aircraft, start over. Your consistent altitude and heading choices you implemented will make it feel like you’re on autopilot.