[lupatus]

How did you identify your niche (personal interest and hope it worked, or did you evaluate it with metrics of some sort)?

Any recommendations for payment processing and goods delivery services?

[flyosity]

The niche worked out because it's what I'm most excited about :)

I use Quixly for payment processing, it's the service that Pictos icon set uses because Drew, the creator of Pictos, wrote it himself. It's outstanding and very cheap. I highly recommend it for selling digital goods online.