Yes, it aint easy, but once you have where you have to hold the slide then it becomes a bit easier.
In standard tuning you can't use the slide between the frets as you would with fingering (excuse the expression), if you want to play slide on the 5th fret, for example you have to place the slide on the bar between the 5th and the 6th fret, then you get the sound requirement of the 5th fret, if you get my meaning.
Some bands like zz top, when playing the slide tune their guitars differently, but I cant remember how.......derrrrr.
Good one to practice too for slide and fingering is "Bad Horsie" by Steve Vai.........
Also, try the lead break on "Tush" by zztop as that is all slide, it teaches you where to place the slide quickly....
Just my thoughts anyway.....