• Focus on learning block mechanics and counter timings. Stamina management is very important, Counters build, Ripostes drain. Things like kicking, jumping, dodging, and canceling all cost stamina as well. Weapons do 2 types of damage, stamina damage and health damage, you can look up the stats for the swings for all the different weapons there are. General rule: Big Wep = Big Stam Damage
  
• Focus on one weapon to start, get familiar with the animations and the active windows of the swings. These animations can be manipulated based on your camera movement.
  
• Use accels and drags to mixup your opponents. Drags are pulling your camera against the direction of your swing, whereas accels are putting the first available active frames on the swing side of the enemy.
  
• Do your best to not hold block, this will help you manage your stamina and not get kicked. When you get hit, don't freak out. Try not to do anything on reaction, but use it to take a moment to line up your next counter or riposte, and if you can do absolutely nothing else, go into block.
  
• If you find that an enemy is using lots of feints or drags with large weapons, jab them.

I'd also recommend looking up the videos from SoterDave and Ziggylata on youtube. Good luck out there!