You should probably begin by focusing on maneuvers that are executed with a particular hand. Once you have those down, learn the same maneuvers, with your off-hand. At that point, start learning maneuvers that require both hands to be active. Then, just make sure to keep practicing. You don't need anyone else with you to practice, but sparring is important as well.
The following videos are applicable in a lightest touch LARP, but are intended for a LARP where your swings have to be hard to be effective. The most important difference in a lightest touch LARP is that you can focus on speed and you can swing with your wrist, if your sword is light enough.
Almost all of the videos below are taken from BrennonEH's youtube channel, which I found linked from LARP Ohio back in 2010. Most of these videos show shots or guards performed with just one sword, which is understandable if you remember my first two pieces of advice.
Here are some miscellaneous, relevant videos:
Holding your weapons
There are three ways that you can hold your weapons:
- One up, One down. In this style, your off-hand weapon is down, preferably completely vertical (possibly with the tip further out than the handle) or completely horizontal. You will do most of your blocking with the off-hand weapon and most of your striking with the "up" weapon.
- Two up. In this style, you will parry blows or block with the pommel of your weapon. This is my preferred style when fighting florentine, as I can block with either weapon and strike with the other.
- Two down. I don't understand the point of this style, but I've been told it offers you additional defense. I disagree, as your shoulders and wrists become an easy target.
Stances
Grip
I imagine you should be using Modified Saber or Saber Grip.
Guards
Shots and Wraps
You will want to learn and practice a variety of shots with both hands:
Pulling Blows
It's important to know that pulling your blows does not mean your swings have to be slow. There are a few main ways that you can swing quickly without hurting your opponent. This video shows a particular fighter (Blue) swinging fast, but soft.
- Swing quickly but without any force behind your swing. This is easy if you use your wrist or if you just swing with your arm relaxed. In this case you don't have to pull your blow because your swing is already soft.
- Swing with any amount of force that you want, but just before your blow would be connecting, start to pull back. The blow will still land and you can continue to pull back to start another attack.
- If your weapon has enough whip, you can swing for just in front of the person and the blow will still land.
I personally use an ultra-light long sword with a carbon fiber core that does not whip. Since the sword is light enough, I'm normally able to get away with only using technique 1, but if someone complains I will also start to use technique 2. This is likely true for you as well - use technique 1 for most swings, and then use technique 2 when it is not sufficient.
Practice swinging softly but quickly whenever you practice the above shots. It will make it even easier.
Sparring
You should spar against the other three styles - weapon and shield, two weapons, and single weapon. You may want to spar using the other styles against an opponent using two weapons in order to better see what both of the style's weaknesses or strengths are.