Shadow Badminton

This is to practice the correct movement and technique without actually  hitting a shuttle. Get a partner to help direct you to the areas of the  court, making sure that you cover the backcourt, midcourt, and the  frontcourt with both your forehand and backhand.
Commit fully during this practice as you would in any competition.  Imagine that you are playing against a world class player. It will  definitely improve your movement on court and fitness.

Wall Rally Drill

Take an old shuttle and hit it against the wall.  Hit the shuttle with your forehand and backhand, straight or diagonal.  It can be used for practicing almost every stroke. It is a good way to  improve footwork, strengthen the arm and wrist muscles used in  badminton.
The wall should be at least 20 feet high to accommodate clears. The  practice will be more effective if you can show the height of the net  with a chalk line or a string, 5 feet above the ground.
As the shuttle rebounds so fast from the wall, your wrist will  naturally come into play. You will learn how to switch grips at an  instance as well. You will be amazed on your improved reflexes the next  time you step on court.
Hitting a shuttle against a wall is an effective practice at all levels of plays.

Multiple Shuttles - Overhead Strokes

The more shuttles you have, the better for this  routine. The feeder plays the shuttles into different areas of your  backcourt. You will then use your forehand, backhand or around the head  to play the clears, drop shots or smashes. Return to your base position  after each shot.
This badminton drill is meant to improve your speed and accuracy in  executing overhead strokes. You have to remember that merely reaching  the shuttles is not enough. You have to play quality shots to the other side.

Multiple shuttles - Net Play

Again, you will need a lot of shuttles for this routine. The feeder  throws the shuttles to your net area. You will then decide whether to  play a net shot, a net kill or a net lift with your forehand or  backhand. Return to your base position after each shot.
This badminton drill is meant to improve your net  play and your movement on court. The quality of your return is  important. Pay attention to it or this practice will not be effective.

Half Court Singles

Playing half court singles can improve footwork and  increase stamina. It will train you to play more accurate shots with  all strokes as well. It is fun to play and effective in improving your  game.

King of the Court

This game is useful when you are with a lot of players. It is enjoyable  and can improve your overall game. It is played with the normal rules  and regulation. You can set the winning condition, normally whoever  reaches 3 points first wins.
The winner will stay in the court as king while another player will  take him on. The king will stay on until he looses. The eventual winner  of that duel will then switch to the other side of the court becoming  king.

2 Versus 1

If you want to improve your singles play, this is a  badminton drill that you can't do without. It is played on a singles  court and is great for improving fitness, speed around the court,  footwork and shot accuracy.
The two players on one side of the court must assume a front back  position and play as they would in a singles match. You will then be  able to play in a very tough and pressured condition, enabling you to  raise your game.

World class players put in a lot of effort during their  Badminton Training. If you aspire to be one, you should do that too.  Practice in the above Badminton Drills and I am sure you will come off  a better player.