Dropping endings can have several causes, but they always lead back to attention to detail.
And if attention to detail is the problem, then the solution is merely to
PAY ATTENTION TO THE DETAILS.

The best solution for those who drop their endings (s, ed, ing) is to read their notes,
type their tests, grade and analyze. That can be hard work, but it will pay off big time.

For those who insist on instant gratification, there is a easy fix that has been
known to work like magic. When you drill at home, reduce the volume of the drill.
Do it little by little, and you won't really notice the volume reduction.
As the sound becomes lower and lower, your brain will turn its full attention to the task of
making out each word -- including endings.

It sounds ridiculously simple, but it does work. Best of all, it's pain-free. No hard drills.
No mental hoops to jump through. Just do your regular drill, but do it at a reduced volume.

Stephen Shastay

Steno Rebel