If your incorrect habit took 1000 swings to develop, it will take 2000 corect swings to change. You will need someone to regularly watch your swing. You can also practice your correct swing by doing so in front of a mirror-with or without a bat. Possibly invest in a nerf or soft bat while in front of a mirror for obvious reasons. This will take dedication and persistence on your part.
1. Practice keeping your hands back and rotating your hips.
2. Bring your hands in front after rotating hips
3. Extend your hands after 1&2.
4. Freeze during all steps and practice them over and over again. The key is for muscle memory to take over and for the swing to become natural.
Okay i have the same problem... my batting coach said that i was doing to much with my shoulders... make sure u just focus on 1 thing at a time and fail at everything else until you get that one thing right and then focus on the next... it takes time trust me... it took me about 2 months to just get my shoulders right... so technically you're not "dropping your hands" you a just leading your front shoulder up which causes you back shoulder to go down and forces you to swing upwards to catch up to the pitch and hit it... if you are hitting pop-ups then this is why... it's not that your a bad hitter you just have to focus on one thing at a time and take in steps and take it slow... make sure you get one thing right before moving onto the next.