|Liz Steel's sketching gear|
I was trying to think what my advice would be and it came down to 3 things:
1 - Sketch only in ink for awhile. Put away the pencil and eraser for sketching. Or if that is too scary you can just make a very light and very quick pencil drawing and then go over that with pen. I have found that the more I sketch with pen and do contour sketching in particular it helps improve my accuracy faster than pencil sketches do. I use Lamy Safari fountain pens with various inks alot but also Staedtler pigment liner 0.5 or 0.7 and Pentel Pocket Brushpens ( I cannot live without them)
2 - Get a sturdy sketchbook with at least 90 lb paper. I prefer hardbound ones to wirebound but use both. My favorites are Stillman & Birn hardbound and softbound, Strathmore with the 500 series 90 lb paper for mixed media and Hahnemuhle sketchbooks (the only place that has those is Wet Paint in St. Paul, MN. - they are great for ink but pencil and watercolor or gouache works on them too.)
3 - Sketch alot with ink. No erasing. I think quantity is often more important than quality because you just improve the more you do it.
Here's the link to Liz Steel's blog where she offers tons of great advice about urban sketching. www.lizsteel.com/ I was lucky enough to enroll in one of her workshops for this summer's symposium in Chicago. It will be fun to meet her after admiring her work for years. I found my way to Urban Sketchers from her blog years ago.
Hope this is helpful! If anyone has more advice please add it in a comment. Happy Sketching!!