Each time you do randori,  you should be clear about the kind of randori you are about to do. One type of randori is what I call "comfort zone randori", where you go in there and just try to catch your partner with your favorite techniques.

This is probably the most common type of randori. Most people do this type of randori without even thinking about it. It's a very comfortable mode to be in because you're just doing what you already know and not trying anything new.

It's okay to do that occasionally. Randori is meant for learning but sometimes, you just want to enjoy doing some sparring. At times like these, go for the "comfort zone" randori. But if that's all you do, you won't improve. As with other things in life, in order to improve in judo, you need to get out of your comfort zone and do purposeful randori.

There are many different approaches you could take to improve different aspects of your game. You could decide, for example, that you will use to randori to try out counter techniques. In such a randori, you don't attack so much but rather, you purposefully place yourself in such a position that it would tempt your partner to attack you a certain way. When he does, you try your counter. You'll probably get thrown many times but that's okay. You need to do this to practice your countering abilities.

You could also use randori to try combination techniques. So, you don't do any single attacks. All your attacks during the randori should be combination techniques.

Yet another approach is to do only action-reaction techniques. This is similar to combinations randori except instead of one technique followed by another, you push or pull uke a certain way and when he reacts, you throw him in the direction he's going.

If you want to hone or fine-tune certain tokui-waza, you can go into the randori focusing on one technique alone. Of course you should also do a few other techniques as a distraction otherwise if uke realizes there's only one technique you're going after, he will block only that technique. Then, you will find it close to impossible to make it work. So throw in a few other techniques as dummies and when you see an opening for your favorite technique, go for the ippon throw.

There are other variations of the purposeful randori that you could adopt, it's up to you to decide what it is you want to use the randori for. But always have a purpose. That will make your randori very productive.