First of all, this guide is for approach controllers.
Have you ever controlled and felt like too many planes are approaching? What is your first solution to the problem?
For many, this includes giving aircraft speed commands slowing them down to incredibly low speeds like 160 knots and building long lines. This is a very unefficient way to manage your traffic as it brings big and unecessary delays to the aircraft under your control.
I am not saying speed commands should not be used, I am just saying that they should be used with caution. There are some methods used in real life which are great to help to increase efficiency.
I will list these below: (The black ring is the aircraft)
#Vectoring aircraft above the airport
Vectoring aircraft and then turning them onto downwind is great help when aircraft are approaching from two ways, it is also a good way to give aircraft the time for their descent if they are too high.
#Downwind before base
Bringing aircraft onto downwind instead of directly onto base (black is directly onto base, blue is onto downwind before) can give you alot of time depending on how far out on the downwind you tell them to go. For example in the picture above, if you tell the aircraft to turn to a heading of roughly 340 then turn it the 110 degrees left so that it comes to a downwind, you will gain alot of time.
This method is extremely good and effeicient if most planes are approaching straight in (like EGBB for example). Bring aircraft like the blue line shows, then turn them onto downwind, while finally onto final.
#Base before final
This method is kind of like the S-patterns, but just a tad bit easier. By bringing aircraft to the base before entering the final, irpt can give you some spearation which might be needed. Certainly good when straight in approaches.
Then there are also pilots who need to know their stuff. We as ATC can’t stand to tell every plane to slow down to a proper speed before starting to vector you. It’s also the each aircraft’s responsibility to maintain proper separation with aircraft ahead and behind. That’s as crucial part to keeping the airspace organised.