Know your throws and look for the grips that are the most effective with your throws. Ideally you want a set of different grips which are comfortable and effective for you. So sort out what your favorite/most effective techniques are and what grip you need for them, then work for it.
Now that we know what grip we want, we need to get it on our opponent. Don't let your opponent dictate grips. If you ever feel uncomfortable with an opponent's grip, get out of it. Ripping it off is usually the first option. You might attempt a lapel/overgrip/collar grip because that's where the attack is going to come from. Grip the sleeve of the opponent's gripping hand with both hands and push down in a sharp motion. If it doesn't immediately break off keep pushing down in a stuttery kind of rhythm until it comes off. Another method of breaking off an overhead grip is to grab the opponent's armpit (on the side they're overgripping) and quickly stiffen your arm while rotating into them and shrugging your shoulder. This will either pop off the grip or weaken it enough that you can reach up and rip it off.
The one thing people tend to do is take the sleeve first. This gives your opponent a handle on you, since they can now easily grip your sleeve and control that arm. Work on your lapel/collar/overgrip/undehook hand first. Use the opposite hand to cross grip and pull your opponent in to make it easier to catch the grip you want if you're going for an over grip or underhook. Once you've got that hand set the sleeve is easy, just reach out and grab it.
You need two hands to control both sides off your opponent. Letting go with one gives them free reign on the one side and you can't block or control them. Be aware when you're both sunk in gripping you need to be doing something with a hand if you're letting go, be it an attack or a change to another girp. Make your opponent react to it so they don't have time to attack. The ideal time to attack is when your opponent only has one hand on you.
