After playing this game for a few months primarily as a 2h/polearm I find two main things 
holding me back from improving beyond where I am:
- Wrong blocks. I find it very difficult to block correctly consistently when you have to 
turn and use a lot of footwork. Good shielders that facehug and encircle well get me almost 
every time, as the combination of having to turn, block the correct direction and most 
importantly see the way the strike is coming is too much for me. I also end up leftblocking 
when I try to upblock, a lot. This comes with more practice I'm sure but it's frustrating 
right now.
- Although I believe I have pretty decent footwork, my offensive capabilities are limited 
and need to be more diverse. I don't feint enough, much at all really and this is a problem 
against someone who can block well. Also my most important offensive problem is also due to 
mouse control (ugh) is that after a successful block I won't return the strike from the same 
direction I blocked in, but rather the opposite direction, which slows down your attack 
phase enough that someone spamming can get another strike in. Again more practice but 
frustrating. I also need to use more overhead attacks because upblocking seems to be a 
problem for most the playerbase.
And then there are a few minor things such as:
- Running at someone with a chambered attack when their weapon is much longer than your own, 
or has a thrust chambered. Sometimes I do this because I'm just not paying attention well 
enough.
- Trying to engage an enemy who is currently in a stack of friendlies from the front.
Running in to engage with a chambered attack from the front is almost always suicide against 
anyone good. By the time you wait for a clear shot they've already cleaved your teammate and 
the next swing will be for you, and unless you were clairevoyant and released your attack 
before he even killed your teammate, he will most likely hit you first.
And now a noob tip from myself:
- Here is a common situation: a player that you know doesn't block much is running at you 
with a chambered attack (but not a thrust, this is important) with a weapon either shorter 
or not much longer than your own. Run at them yourself with a right attack chambered and as 
you're about to step into melee range stafe/turn to your left (going to his right) as you 
release the attack. The speed bonus on this hit is massive as you're both running at each 
other full speed. But since you released the strike from your right as you're moving to the 
left, your strike will hit him incredibly fast, sometimes it will be so fast the enemy won't 
have even released his chamber by the time he's hit. You will also hit him with the money 
part of your weapon arc, and this drops most non-tincans with a STR build.