I really think that many people have struggled in this area.
I know I have.
After doing considerable research on the subject, I came to one conclusion...
...
STOP OVERUSING YOUR BICEPS! This is actually a very important technique for rock climbing, that I oddly never transitioned to the gym.
Rock climbers quickly learn that you have to stop clenching on, and pulling too much with your arms.
If climbers don't put more focus on the legs and back, they burn out quickly.
Putting it simply, you need to use as much mental focus as you can, and concentrate on contracting your lats.
Let your hands hold on to the bar or weights, and keep the arm muscles as relaxed as possible.
Think of your arms as a couple sticks (or logs, if that makes you feel better) with joints.
So only your back muscles are pulling the sticks (logs) in order to move the weight.
By overusing your biceps and other arm muscles, you are taking too much of the weight off your back muscles.
Your arms tire out before your lats have a real chance to get any real work done.
The best thing you can do to improve, is to lower the weight you use.
If the weight is too heavy, you won't be able to put proper focus on your lats.
Once you become more accustomed to keeping focus on your lats, bump the weight up.
Give this a try for a while, and I guarantee you will start to notice a difference.