There are many ways of concentration, but the best way is the repetition of a word. For instance, if a person wants to concentrate on balance, he cannot make a form of it before his mind because it is an abstraction. But if he closes his eyes from all other things and repeats to himself: "Balance, balance, balance, balance, balance", naturally each time he repeats "balance" it makes a picture in his innermost, a picture of balance, and in everything he does he sees that picture reflected. So his life becomes balance.