Grip is something that is hard to train because there aren't a lot of traditional exercises that people think of to strengthen this part of the body.
Fortunately there are a variety of exercises that you can be doing that will help you improve your grip and make it much stronger.
Find out what these are so that you can start working on it.
The first is to just workout with dumbbells.
As you are working out with dumbbells, you are passively working your grip since you have to hold on to them.
This over time will help your grip get better especially if you are doing a variety of motions.
Do more pullups.
These can help your grip.
For an advanced technique drape two towels over the bar.
Do pushups while holding onto the towel.
This is much harder to do but it will help your grip making it stronger.
Try the wrist roller technique.
This is where you use a round bar, a string, and a weight.
Tie the string the middle of the bar and the middle of the weight.
Hold your arms out in front of your and roll your wrists winding up the string all the way up and all the way back down.
This will help your grip and forearms.
Get wrist grippers.
These are the devices that you see that you can squeeze in your hands that have resistance.
Do this while watching television as it's something that you can do passively.
Do the exercise called the farmers walk.
This is where you hold very heavy weights in both hands and walk across a room.
Go back and forth going with very high weights as it's challenging.
The more weight you use, the stronger your grip will become over time.
A very simplistic exercise is to simply get a towel wet and wring it out.
Do this over and over as it's a challenge to your forearms and your grip.