This is designed to help you get the most out of selling your old (or newer) comic books on eBay.

Descriptions
Always try your very best to describe the events in the book (if selling one) or the basic story (if selling a number of issues). This gives people, who may not be looking for that issue specifically, something that catches their interest.

Check the issue and see if it's the first appearance of a key character (a quick google or a copy of Wizard magazine will tell you that) or a major turning point in that universe - if it is mention that in both the title and the description.

Be honest about the books condition - if you're not a professional grader say so and describe as many faults as you can see on the book.

A useful guide for grading the condition of books can be found by googling 'mile high comics' and 'grading'

Images
Try to take good quality photos - on older books take large high res images if possible and store them off ebay to link to (alternatively offer to send bigger and better images when requested)

On Bronze Age (1970 - 1979) books or earlier (if the books are worth more then usual) take three images - front, back and inside - this will cut down on the number of questions you have to answer.

Posting
Always try to send books in comic bags (you can usually pick-up 100 for around £3) they provide extra protection meaning less chance of damage being done in the post - card backed envelopes are another good investment as they prevent any damage being done by parcels being folded or crumpled.

Alternatively buy some backing boards (usually around £8 for 100) and place them in the comics bag to protect the item(s)

Misc.
If possible bundle issues into complete story arcs which makes them more attractive to buyers.

Marvel and DC superteam/superhero comics are the most popular if you're selling, there's also a smaller market for Transformers comics from Marvel UK, limited Darkhorse comics, Image/Wildstorm books (now a part of DC) and Doctor Who comics/annuals.

I personally don't see any point in getting comics CCG'd (professionally graded, then sealed in a plastic case), it will increase the books value in auctions a little, but is only really worth it (in my opinion) for high value books such as early 60s/70s X-Men/Spider Man or older Superman/Batman books from the 40s - 70s.

Do your research - if you don't know anything about comics before selling have a quick look on eBay to see how similar books are doing also have a look at MileHigh Comics to see roughly how much the books are worth - but be advised Milehigh prices are usually 5-10% higher then retailer price and upto 15% higher then eBay prices.

Just google 'milehigh comics' to find the site.

Unless a book is considered rare or a key moment for its universe anything in bad condition (writing inside, pages/cover missing etc.) probably isn't worth listing - comic collectors are notoriously picky about getting books in as good a condition as possible.

Some books just won't sell - either they're not highly prized as collectable items, in too bad a condition or they're simply not very good - sometimes in these cases it might be better (and more cost effective) to donate them to your local Childrens Ward :)