Well, so here's my second zentangle - a straight up random pattern, rather than trying to overcomplicate things. This time, I did it in an artist's sketchbook - ie. proper paper. I started off in pencil, thinking that might give me more subtlety. What it mainly gave me, though, was dirty hands. So I swapped back to a black sharpie :D Still, the bottom two patterns are in pencil (bet you guessed).
All this to say, there's definitely a long learning curve still ahead of me. I do find it quite meditative, though, actually creating these, even if they're not something I'd want to hang on my own wall (or anywhere else).