Rods are different, reels pull the line in at different speeds for each turn of the handle, colours change, wind changes and so it goes on and on. Each angler fishes differently, but the same basically, as they get familiar with their tackle, they get into set patterns for various species, and will "almost" always do the same things.
When watching someone retrieve a spinner/lure for example. Watch the rod action, how fast the angler winds the reel (and the speed the lure comes in, more important).
The time spent watching and trying to copy a catching method is well spent and worth more than a thousand words, as it is difficult to explain what you do when you are fishing, as it becomes "automatic".
If the angler catching tries to explain or gives you instructions or hints, listen and try the way they say. Eventually you will get it right and a fish will "commit suicide" on your hook/lure.
Once you get that far "confidence" will take over. and you will be on your way.

When boats or anglers are moving out at the beginning of the day, and they come back at the end of the day, LOOK at what is on the end of their lines. This will give you some idea of what you should be doing.

When you see other anglers at a weigh bay, or where they are gathering with their fish, stand in the background and LISTEN to them talking, they may share their days experience with their "trustedfriends" but may not want to "give lessons" on what they did during the day.
This information is too late for that day, but it may be useful in the future, for the same dam/lake.

Try to read as much as you can, about the fish you are trying to catch, and where they live and what they eat and so on. This will help you to understand them (a bit) better, and will help when you have to go out on your own and look for them.

When you are out fishing, keep your eyes and ears open for fish movement. Often you will hear first, and then you will see them, or where they were. Keep watching the area, they will normally come back and carry on what they were doing. Remember what you see, and think about how you could get them on to your hook.

Remember, you are going to lose some tackle, so make sure you have got spare bits and pieces. If you lose something (after trying your best to get it back), do not get all angry and upset about it, rather try and tie on another one and carry on fishing. Enjoy the day out.
If you didn't lose any tackle, the factories would all close after everyone had bought what they wanted. The fish (and Nyami-nyami) have to win every now and again too.

If you are fishing with someone new try their ideas, even they are not the same as your own, you might learn something.

TRY, I know it is very hard, but put back what you do not need or are not going to eat, then there will always be fish out there for you to catch. If you find a good spot, try not to kill everything there, it will take a long time to recover (a year or two), to get back to anything like a good spot again.

The MOST IMPORTANT thing is to give them CONFIDENCE by catching at least one fish. Once you have that they will will carry on forever and never want to go back home.

One of the most important things to try and achieve when you "volunteer" to do this, is to find a spot where they will catch fish, maybe only a couple of big ones, but you need to keep their attention on the job at hand. As soon as they lose interest or get bored, you are in trouble. The sulks, screaming and shouting, fights and all break out, and you will explode or want to drown someone after a while. (Please try to get them ALL back home in one piece)
"PATIENCE MAN, PATIENCE"
What is that he says? Well my Grandmother once said :-

Try to explain to them why you are doing what you are, and they will then start to think (heaven forbid), and may start working it out on their own, and you might get some fishing in for a change.
For the really despondant (learners only) in the boat, just hook one and then tell them to use your rod (slack line), and then tell them that they are getting a bite and to take up the slack, and let them enjoy the feeling of the catch, and get their confidence up.
After that you will more than likely find that they seem to do better on their own than before.

The main things you need to try and teach them, (so you can get some fishing in) are the basics :-
Casting, Knots, and the baits and how to put them on properly.
The rest comes with the experience of having someone like you to take them out, and show them "spots" and "areas", and hopefully explain why there.
They will slowly establish the simple patterns like "by the edge of the weed" or "in the hole" or "by the tree", and having learned through experience, these will always be remembered. (They will also remember all YOUR spots to tell their folks too)

Above all the fishing info, please remember to teach them about the effects of the sun, crocodiles holding your hand and all the other safety issues, the last thing you need is a disaster.