I usually tap on the first string a couple of times then I slide two frets down from the fret I was tapping on, then I just do the same slide on the string above it and so on. Did that help? Another trick I do is when I play legato in the 5th-8th I sometimes bend the string with my right hand by the tuners. :)
And when you do a trill you can switch pickups really fast to creat a kind of wah wah sound or similar. Yngwie Malmsteen does that sometimes. :P