As a Web designer / Designer I hopefully hold some merit on this here topic.
Logo should be able to be compressed into an icon. (for mobile)
logo should look good in black and white.
logo if used for branding, needs to be small in size.
logo needs to be identified from a distance without any working.
logo should not loose style over years (say 5? is it still cool)
Does it look good on a black/dark grey background?
Does it look good on a light/bright background?
Does it look good on a multicolour background?
DO NOT use stock images or clipart (build in brushes in photoshop or google images) a logo must be unique.
USE geometric shapes, a long logo (my really really long brand .com) is not a logo.
Create your logo in Vector format, this allows it to be used for other things like scaling a billboard, or shrinking to a mobile without it looking squished, loosing detail or becoming un readable.
dont confuse LOGO with Branding. Not sure? look it up your on the internet.
LOGO's are Like quotes. It takes time to make a good one.
do not style the logo,
do not put text on the logo
do not put the logo in a box.
do not put the logo in a frame.
I do not like green eggs and ham
Do not add stroke (outline) to a logo
do not add shades to a logo. (look at other top brands for example.
Use LOGO Thief website to check how close your logo is to others.
and Finally SKETCH EVERYTHING!You will be surprised at something you hate is actually pretty cool to everyone else.
Good luck and sorry for the (i seem to hate everyone) post.