I’ve been knitting a hat with DPNs. How do I tighten the gaps on it? Last time I knit with these needles I had to do increases on these gaps, so they really can’t be seen. But this time it’s really obvious.
Also, how do I prevent them? Any tip AT ALL will be thanked 
Those are called ladders and are very common with DPNs.
Several things to try - If you’re doing ribbing make sure the first stitch on each needle is a knit. Try tightening the first or second stitch on the needle. If you tried that and it didn’t work you might be pulling too tight so the yarn is stretched and when it loosens it leaves a gap. You can also move the join over a stitch or two ever couple rows so it’s not so obvious.
I knit socks quite a bit and get laddering no matter what I do or try. I’ve found that the first washing usually takes care of the problem.
Do the first stitch on the next needle as you normally would.
Insert the right needle into the second stitch on the left needle and give a firm tug on the working yarn to snug everything up. The tension on the first stitch will help hold the yarn firm.
You can also fill the right needle and then do two more sts from the next left needle before beginning with the empty needle. This moves the looser stitches around the item and they generally disappear after washing and/or blocking.
From now on I’ll knit 2 stitches from another needle with a full needle and then use a free needle to continue. (This might not make sense, but I understand myself )
This works with hats, but if you are making socks or something you want to be careful you keep your stitch count right for the heel.
As long as you mark the beginning of the round it’s easy to count the sts and get them back on the appropriate needles for heel flaps and toes.
:woot: