How do you change weapon and armour on a follower?

Talk to them,
say you need to trade something with them,
give them a better weapon or armor by finding the weapon/ armor and pressing X for xbox, don't know about PC. (if its not better they won't equip it)

Here is what I do on master:

You just DON'T fight them and take whatever you need and run.

Or if you're foolish enough to even try:

• Make use of potions
  
• Make use of poisons
  
• Don't forget to use your shouts

And what you should always do:

• Buy heal/magicka and resistance (!) potions
  
• Upgrade your gear with smithery (yes, you can do that without taking perks)
  
• Give your companion good armor and a good weapon
  
• enchant, etc.

Quite a few good tips there, I'll keep them in mind though I'm only playing on expert.

There is no super attack move when dealing with powerful enemies. Sounds like you`re talking from a beat-em-up console game.

Your tactics in an rpg are infintely more in choice. If the enemy is too strong you have several options:

1. Hit and dodge, hit and dodge. It works sometimes. hit him, run back to avoid his swing, or run behind a rock. wait for him to finish his swing, hit him again. Keep doing this, avoiding all his blows until he dies. This is very hard and you need to be a whiz with keyboad and mouse control. Probabaly not good for gamepad as you need absolute control.

2. Get somewhere high and archer him to death. i successful killed a Spriggan by putting myself on a cliff where he couldn`t reach me and hitting him until he died.

3. Get a companion and use him to keep the monster busy while you batter it in the back until it dies. Works quite a few times.

4. Eat lots of health potions and food even.

5. Run away and\or jump in a river. Some creatures don`t like water.

6. Skirt around and avoid if you see in a distance. Deal with later.