First, get naked. Don't want to see your sox or tshirts.
Make sure photos you send here are in FOCUS. Nobody likes to squint at fuzzy pics. For closeups, use the Flower setting on you camera.
Check your computer photo program and see if it includes an editing ability. Most do. Or get an inexpensive one like ACDsee, Corel, or Adobe Photoshop Elements. Then don't be afraid to crop or edit your shots. Show the essentials, not a lot of other stuff.
Watch the background. If you're cumming, do it in front of a dark background, the nice spurt is lost if it's a light one. And cluttered backgrounds detract from the quality of your fine pecker or body.
With digital cams, take lots of shots--check as you go and repeat any that don't look great.
Lots of wonderful pix here, keep 'em cumming.
All good advise!