You need to open a Paypal premiere or business account. Click here to open or upgrade your Paypal account to a premiere/business account. This will allow you to to be able to accept credit card payments. Most buyers pay with their credit cards so it is completely worth it.
Next open an eBay store. I recommend you open a store as it provides a way for you to list more of your items at much lower listing fee costs.
I use Blackthorne to list my items since purchasing SAP will give you free access to Selling Manager Pro for free. Selling Manager Pro is a must-have since this software will automate a large part of your business. You should subscribe to Selling Manager Pro regardless of what selling tool you use to list your items. Selling Manager Pro will automatically send winning bid confirmations, payment reminders, and automatically leave feedbacks for your buyers. I use Blackthorne to list my items since it is much more feature-rich than the freeware program, Turbo Lister. However, as a beginning seller, I recommend sticking with only the Turbo Lister software as it is cost-free and provides all the features you really need. To get more details on these programs, you can enter eBay's listing tools live chat.
Also, consider opening up webspace. If you want to go big in business, it is crucial that you must open up a webhosting plan and have a website to sell more of your products to your customers. Even if you don’t plan selling products through your website, just let it act as an “about our business” page. Such a page is not hard to set up at all, yet it will significantly increase the credibility of your business. I recommend that you get a webhosting plan at 1and1 Webhosting as in my experience they are the most reliable webhosting provider I've been with and their prices are extremely reasonable. If you do not have a domain, you must first register a domain, and then sign up for webspace. The cost of running such a website is so trivial that it’s really a must-have to get one up and running right away.
Now that everything is set up, you are ready to start business!