I've seen some killer textures for sl avatars, and that while a good start has a number of issues, and doesn't look that attractive. (No offense intended.)
Look at the corners of the mouth, and the width of the nostils for issues.

Textures for the sl figures MUST cover the specific polys that are used in modifying the characters.. otherwise you get things like a figure with large lips, but textures for them that bleed over, or don't reach the edges.

While you can create poses and animations in poser, and textures in any 2d paint utility, anything else must be created in sl, and characters cannot be imported in any way shape or form.

I've quite a number of things for sale in second life, and after a year's time, MIGHT have made maybe $75.. for many hours work.

If you create things for sl, don't plan on getting rich, or even possibly pay for land in sl. The time investment was a waste of time.

if I had to figure out the money I made vs the manhours used, I'd say I was making a quarter ($.25) an hour.
 
It was amusing, but the constant server issues and changes, couples with learning a whole new 3d building and scripting system just wasn;t worth the time invloved.

Way too many people take way too many things way too seriously.