What's a good way to start selling original art?

It's hard to give you a great answer without knowing your chosen medium. However, it would not hurt for you to start networking with local art galleries, and your mention of IKEA leads me to believe that you may be near a big city which is even better! I'd also suggest to contact art departments and local colleges and see if you can speak with one of the directors or professors in your chosen medium about it. Perhaps they may have some helpful suggestions.

I have a few friends who are painters, and they have networked with local small businesses who hang their work for sale in exchange for a small percentage of the profit. Perhaps this is something worthwhile as well?

I don't think I know of a really good way, but many artists sell their work at summer art fairs. I haven't done that in over 30 years, so I can't give expert advice on what sells. I have my photographs on a website, Fine Art America, and make an occasional sale. Competition is fierce there with hundreds of other artists displaying their work. I'm not an active marketer and mostly make print sales by word of mouth. Anyone who can make a living these days selling their art has my admiration.

Hi
It took me allot of " balls" to get out and talk about my art , but I started to sell mine through doing commission work which sucks because people change their minds and most likely they want a copy of someone else's art , but that's how I started , I stoped marketing through cafés or store windows they just didn't take care of them well enough !
After I made my Webpage and marketing through Facebook , my artist carrier took off !
Just don't be shy !! Brag brag brag about how good your art is !!
Good luck !

Have a art auction and make and pass out flyers to your friends and family.

Try checking out becoming an artist for Society6.com!