If you have an eye for design and some experience of creating websites, then you could offer your services as a freelance web designer. You will need to create your own stylish website and have a few other projects that you can show potential clients to demonstrate your skills. You will also need to initially spend time emailing businesses to promote your services and find work.
Multi-vendor marketplaces, like ThemeForest, can be very successful. Chose a niche and create a vendor website for it. Your marketplace could be anything, from a platform for local artists to sell their work on, to an online digital product store. Once set up, invite people in that industry to sell their products on your site. You take a percentage of their profits when items sell.