The drop and lift drills is one of the most basic and simple drills in badminton. You can try this out at the nearest badminton courts where you will need to employ a feeder to feed you the shuttle.
Do not assume the partner hitting time and also do not move before or same time as your feeder is making a shot.
When you are hitting a drop shot, you are hitting from your rear court to your opponents front court. Meanwhile, your feeder send back over to you the shuttle to your rear court.
Practice makes perfect. Be strong in your basic, then you will become a good badminton player.