I've found that Online websites can be an additional way to reach others well, depending on what site you use.
While you didn't ask about what sites work well or how to set up your own .com page, let me tell you what I've done.
Ebay- avoid it: Too expensive, and unless you have one of a kind items that are on the high end scale you won't make enough from "Buy it now" or auctions to make up for the cost. Ebay is best for mass manufactured items or resale.
Etsy - This site is specifically for hand crafted items. Granted there are a lot of maillers on this site but the traffic to this site are people that are looking exclusively for hand made items. Further, if you are looking for hard to find items, supplies or graphic design items such as banners, avatars, or business cards, there are TONS of Graphic Designers that are offering high quality services for low prices.
Sites like Etsy has easy to use shipping and mechant gateways to calculate shipping and multiple item invoicing. Worth the fees (Ebay again more expensive if you have a store and not auctions as it charges a flat fee on top of listing and picture fees).
As you can tell I'm very PRO Etsy. The other thing I like about Etsy if you are looking for supplies, findings or anything else that is hard to find you can post a picture and description with the price you'll pay and someone may find it and fulfill your needs. This is called Alchemy. I've made several local and national contacts through this feature.
While I respectfully disagree with AoM that you may not increase your income with a website, I do, wholeheartedly agree that its a very effective tool to give loyal customers information, history and upcoming events or promotions with your business.
If you use business cards with face to face sales ALWAYS have your website address on the card. I plan to do craft shows this spring and summer and will offer a percentage off to customers that 'find' my website and purchase items. Face to face sales, whether at craft shows, private parties or just at the office or passing by, I offer 10 percent off if the customer uses pay pal, instead of a check. No bounced checks and you can do it over cellphones. Easy peasy lemon squeezey. Cash is always accepted, but does anyone use that anymore?
Pictures... Ask Lawless Lady what crappy pictures I had on Ebay. Disaster. Get good ones done or learn how to do them yourself. A Light box is essential for quality pics. I've seen scanner pics and they can be decent. Pictures sell your item. As many have said if you can't see the splendid work, what's the point of having a picture at all.
I made a light box from this blog: http://www.strobist.blogspot.com/2006/07/how-to-diy-10-macro-photo-studio.html
I bought a $5 tripod ( on ebay LOL ) for my older model digital camera. A tripod helps prevent shaking and blurs in your pictures. All in all I spent about $30 in items to make the light box, set up lighting and secure my camera.
Good luck in your efforts, and remember, lots of good advice here on the forums. That's how I learned.