A very important rule, in particular for beginners is that:

You can declare every ball for unplayable.

What happens then? You receive one penalty stroke (due to inability) and the ball is dropped

• Either: Two club-lengths of the spot where the ball lay, but not closer to the flag. (Except in bunkers, where the ball may not be dropped outside of the bunker)
• or: On the line from the hole through where the ball lay
• or: At the spot where the original ball last lay.

Did you notice the advantage you are getting?

Let us imagine that your ball is lying somewhere in the rough and you know that you will not be able to play it from this spot. That is no big problem ? with only one penalty stroke you can locate a wonderful place on the course (on the line from the hole through the ball) and drop your ball there.