outline problem

[Hamvid]

SO!... i have a tendency to depend heavily on the use of outlines when im photoshop sketching. some artists use the outlines of their characters to their benefit and bold them out even more. that's a great style- but i would personally like to do away with outlines in my finished products all together. i realize this takes great control of lighting and color, but im pretty stumped. i have no formal training outside of photoshop photo manipulation, so i tend to stick to that side of photoshop. ive been trying to make use of what my wacom tablet can do, practicing every chance i get.

so- does anyone reccomend any specific tutorials/tips for sketching in photoshop for styles that don't involve line art? any help would be much appreciated.
for samples of what ive done- you can check out my page at h4k70r.deviantart.com/