I made a topic about Larp and combat. Ignore what I say about archery but I think the rest is sound. If you don’t want to go into loads of details then here are a few quick suggestions.
The most important rule in empire’s battles is good team work. This means stick with your allies and doing your best to cover them because if you do this, they will be there if you go down.
Be aware of your surroundings. I played an Orc last event and I managed to get behind the retreating imperial forces and cause a bit of chaos. You also don’t want to tick over roots and things like that as they can slow you down or injure you.
Keep your head up. If you drop your head, you will be more likely to be hit on there. It also means it is harder to see what is in front of you which makes defending harder. If you are doing to duck, do it at the knees instead of at the hips. You will probably have to move back as well, just to be sure. It is better to make two moves and go too far out of combat then one more and not get far enough.
Look at your physical attributes and see how they can help you. If you are tall then you might want to go for reach, if you are small you might want to go for speed.
Your biggest down fall will probably be worry. When a weapon comes towards you, it is natural to shrink away. If you have any friends, it would be a good idea try to practise light sparring with anything that won’t hurt being hit with. As soon as you lose your cool, the enemy can push forward and overwhelm you.