There is one thing that can’t be stressed enough and that is to increase the amount of weight that you are lifting. Lifting the same amount of weight, even if you increase the number of repetitions doesn’t help as much as increasing the weight. This type of exercise regiment is considered progressive resistance training.
Why do you need to increase the weight?
Your muscles will get comfortable to lifting a certain amount of weight after a while. You have to push your self and your muscles in order to get stronger. But just remember that the increase should be gradual.
If you are using 10 pound dumbbells and you can do 2 sets of 10 reps comfortably then it is probably a good time to increase the weight, not much though. Two sets of 10 repetitions is probably a good benchmark to shot for before increasing that weight.
Always be careful when lifting weight and never strain yourself to lift any amount of weight.