I promised you some tips on capturing things. Well this is one of them. Divide and conquer.
By cutting an opponent we mean separating his group into two, or more precisely, preventing two groups of stones from connecting. If you want to put pressure on your opponent, this is a crucial technique. Taking care of one group is easy. Having to take care of two groups (possibly having to find two eyes for both) at once, now that is not so easy.
But beware! While separating the stones of your opponent you are usually creating two separate groups for yourself as well. Cutting often leads to fighting. Timing your cuts is important. You should first make sure that your stones are stronger than your opponent’s. Otherwise you might be the one who will be under a lot of pressure. Check out these puzzles to get the idea.
Black to play