A lot of slide players will use open tunings to be able to slide whole chords and such, and you might find it easier at first this way in order to get the basic techniques down. One of the easiest slide songs I know (and what helped me to get the gist of slide playing down) was Led Zeppelin's (cover of) "Hats Off to Roy Harper".

It's in an open C tuning: CGCGCE
And ~ shown = to shake it back and forth around the fret quickly.

E---/3--0--/3--0--/12~
C---/3--0--/3--0--/12~
G---/3--0--/3--0--/12~
C---/3--0--/3--0--/12~
G---/3--0--/3--0--/12~
C---/3--0--/3--0--/12~

This is repeated over and over.