Just try to end some, where in between your frets, like in the middle, useing your 1st 2d 3d pinky, fingers of your left hand. Also try this same slide all over the finger-board. Try sliding up plus back down the finger-board.
Practice Practice. Try to check out what your doing wrong and fix it. I can't see what your doing but you can.
If you practice it alot, soon your muscles will "remember" how far you have to go. The muscle-memory is the key to playing with closed eyes. It is very useful. good luck / MC
pick the first note with authority really attack it... and slowly slowly slowly just slide your finger up to the 17th fret. look at your fret hand when you're doing this dont go any faster until you are comfortable at the slow speed and you can hear the second note ring out. -G (oh, once you get that down..its nice to throw in a little vibrato on that second note) :)
a good guitar player that excels at sliding is kirk hammett its does it all the time and probably doesent even no hes doing it but learn some kirk hammett stuff hes always sliding