My dream growing up as a kid was to own a comic book store. However, eBay will probably be the closest thing I ever get to owning my own comic book store. That's ok by me,  I have been selling comics on eBay for close to seven years and have been an avid comic collector for nearly 20 years (I'm not that old, I started collecting when I was just 12 years old). There are a few things that you can do to prepare yourself before you jump into the crazy world of selling on eBay. I will bulletpoint some of the nuts & bolts on how to sell comic books effectively on eBay that will make you lots of money!

• Set up your basic eBay store- give it a good name and customize it! I would start with a basic store so that you can gain some experience. I still use the basic store. It works for me! Keep in mind that the main advantage of using a store is that the listing fees are much cheaper and your store listing runs longer. The  store listing fee for my comics cost .06 cents with a gallery picture per listing. This is a huge savings compared to the auction style listing which starts out at .35 cents. I would say that a majority of your comics will end up in your store.
• I would highly recommend that you purchase an auction template, if you can't make one yourself. I purchased mine from David Grant. He specializes in helping eBayers create templates.  It was $60 dollars or so and the best investment! This will add professionalism to your auctions. Not only does it add flare to your items, it also enables you to quickly list your items.
• Create an about me page! Yes, people buy from people! If you create an about me page, you will personalize the transaction even more. In the future, I plan to have a YouTube video  production of me giving an introduction as to who I am. This will go a long way in getting your customers to trust you.  
• Get Turbo Lister Basic- I use the basic turbo lister (I hate paying fees) this program has been a godsend! I use to do it the old fashion way and it would take forever filling out the forms eBay provides. Go with Turbo Lister, you will not regret it!
• Buy your supplies on eBay. I purchased 100 padded envelopes for .30 cents each! At the store these envelopes run about $1 each. What a bargain! I also invested in a Do Not Bend Red Stamp to save me time from writing it on the package when I ship Media Mail. Buy your supplies on eBay!
• Use PayPal. It's so easy and convenient! You can accept money from buyers anywhere in the world! Also, take advantage of their money market feature. It gives you 5.03% interest on your money! Not a bad return on your money! It's better than ING Direct at 4.5%! You can also use the shipping feature which saves you lots of time at the Post Office.
• Make friends with your local USPS clerk. I have an arrangement where I drop off my packages in the back. I ring a bell and they collect my packages for quick delivery! It takes me seconds to drop off my packages.
• Get a digital scale. I have a cheap Ultra Ship-30 scale that I use to weigh my items. It goes up to 30 lbs, it's cheap, but, hey it works, right?
• Get a good scanner with a fast scan time. I am working with an Epson Perfection 1670 scanner. I can scan a comic within 30 seconds after the scanner warms up. I hope to upgrade my scanner and decrease the time of the scan.
• Use eBay's Marketing tools! I just figured out that eBay allows any seller to create promotional flyers for their customers. It's very easy to customize, I include one with every purchase. This way my customers can see what other items that I have for sale when their comic book(s) arrive! This is a great service and reminds your customers of your store name. Always be branding your store. I think that I have cool store name-IncanSun!
• Ask questions! Go on to the discussion boards and ask questions! Don't be shy. Powersellers have their own discussion boards and I have learned a wealth of knowledge on them. However, they have discussion boards for newbies too!
• Inventory- Many Powersellers will not reveal where to get inventory, but I would suggest that you start looking in the trade magazines for comic book shows and conventions.You can find a lot of good deals and negotiate prices with many of these dealers. I have even bargained with the best of them. Harley Yee is a tough nut to crack! Also, the newspaper and the recycler are good place to look as well. Most of this information you can find online if you type Comic Book shows/conventions in Google.  Luckily, I have a few thousand comics that I can sell from my own collection. My wife grimmaces every time she looks into my closet and it stacked with long boxes full of comics. I have a long way to go before I start buying anymore inventory.
• Always UPOD! Under promise and over deliver! Never exaggerate the condition of your comic book. Be honest, even if you don't know the grade of your comic, let the potential buyers know. Though not always fool proof, a good scanned copy of the book in question goes a long way when it comes to figuring out what grade a comic book is truly in. Here's a quote from a recent customer:

Hello,
I received a book I recently purchased from you today (Incredible Hulk 340). It was in excellent condition. I like it when the product surpasses my expectations. I only wish I would have won more. I'd like to wait on a couple of books ending in a couple of days and also consider a ocuple of other BIN books. Would you mind waiting until this weekend before I make a final purchase? Thanks again, Dan
 

• Finally, share your knowledge and you will be rewarded! Yes,that's right! A guide or a review will help your situation because the information that you provide will help others and your items on eBay will gain greater exposure to other collectors when they read your guide or review!

 I hope that this review helped you. If so please vote for it! I hope to see you as a fellow seller on eBay soon. Drop me a line and maybe I can help you along the way! Best Wishes!