A lot of the lessons out there on the net show you how to play some lead work. What I have noticed is that there are not too many lessons giving you any riffing ideas. I'm not as much into theory as I would like to be, but I try to get by with what I do know. I do know that I‘m not much of a strong string skipping alternate picker; my fretting hand is a lot faster than my picking one. Most of the time, I like slapping a note instead of picking it. Some have called this "the hammer-on from nowhere" technique. It makes the riff you're playing sound a little less "choppy" and a little smoother. I've heard Nuno Bettencourt use this in his riffing with Extreme ("Cupid's Dead" from 1992's 3 Sides To Every Story) and a good example would be Joe Satriani's "Midnight" from 1987's Surfing With The Alien, only there is no right hand tapping here.
This is one idea I came up with in the key of G. The accented notes (>) are the ones that I pick with a down stroke and the notes highlighted in red are the ones that I tap (H*). I also included the suggested fingering for playing this.
When tapping that B (7th fret 6th string), be sure to give that note a little palm mute so it won't bleed into the other notes. You can try this one up and down the neck and see what sounds best to you. Like I said before, I'm not heavy into theory so I don't know what scale this is. I just make stuff up based on what sounds good to me. Hope you can find some use for this in your playing. If I get asked to write something for this website again, I will show you how the Pantera song "Shattered" inspired me to come up with my own stuff. Questions or comments? Send them to guitarslavernie@yahoo.com.