Look for the space in which you are looking to make the run. Point towards the empty space with your arm so that your teammate knows exactly where you want the ball to be delivered.
Now start to make that run keeping in view the offside rule. You should not be making the run before the ball is played, so that you avoid being penalized for offside. Offside is probably the most difficult rule in the modern day game and a player should not pass the line of defenders before the ball is played to him.
Keeping in view all these rules, make the run and position yourself accordingly to the ball.
Now position your body in such a shape that you are best suited to receive the ball. The position depends on your stronger foot and where the ball is played.
Usually the two centre backs of the opposing team will come and intercept the ball, but if the ball is played to perfection, you have to make it count by making your way through the defense and finding the back of the net.
Making the run will definitely put immense pressure on your opponents and catch them off guard. The ideal scenario will be if you put the ball at the back of the net.
Perfecting the deep run comes with practice so put in the required effort on the drills to make your place in the team.