Workout is the process of increasing the size of muscles and define them. If you want to make your muscles grow you have to do a short but intense workout with few repetitions but doing slow movements. If you want to define your muscles you have to do a long and soft workout, with a lot more repetitions but doing fast movements, because that will burn your fat around your muscles that is hiding them and you will be "educating" your muscles to stand in a more defined position.
Something that's important for working out that we never care about but that is very important is to focus. If you're distracted you won't grow as much muscles as if you were focus in your exercise.
Remember that muscles need 48 to 72 hours of rest so do a full workout every other day our alternate your muscles for the days of the week. You can even do a workout schedule.