What skills do lifeguards need?

Not much is necessary. The ability to swim a somewhat long distance(normally 20 lengths) is required. Everything else is explained in the course itself. Your instructor will normally demonstrate the technique and as long as you are paying attention, you should be able to imitate.

It is all about technique and a little bit of physical strength, once part of the course has someone grab onto you from behind to simulate a distressed victim who thinks they should be saved first. They will teach you the technique to break this hold, without actually injuring the person.

Another thing is using a backboard. This was the only part of the course that I found difficult. Strapping victims to the board can be difficult and tedious, especially when you are simulating a head injury, requiring you to hold their body and head perfectly still.

Hope some of this was helpful to you.