Are you a DIY kind of person? I've compiled some of the projects I've made throughout the years.
The Putting Board is a 3 foot board which has a smaller than normal hole, that can be perfectly leveled from left to right. This enables you to practice short putts with a slight incline which will help you engrain the feeling of hitting the ball hard enough to get the ball to the hole.
After a lesson with an instructor, I was looking at some of the training devices he had. One was a "putting arc", which guided the head of the putter along a specific path. The problem I found with this device was that the arc that you had to putt on was not adjustable, therefore it only fit players with a specific lie angle or shaft length.
So I came up with this device, the "Putting Plane". Instead of having the head ride on a specific arc, the shaft of the putter will be guided by a horizontal bar. In essence, this device is self-adjusting for shaft length and/or lie angle. On top of that, it's cheap to make!
Long drive guys swear by overspeed training, and it's becoming quite popular. Build your own 3-club set of training clubs with these instructions!