A curved line and the letter H indicates a hammer. The first note is played, but the second note is produced by hammering the left hand finger onto the same string.
A curved line and the letter P indicates a pull-off. The first note is played, but the second note is produced by then pulling the finger off the first note.
The letter S and a straight line indicates a slide. If the line comes from below the number, slide from a lower fret; if the line is above the number, slide from a higher fret. A slide can also be indicated by a straight line parallel to the string when sliding from a specific fret.