The first two points are the best, I think. A niche has a better chance these days. Think content curation. Actually, think content curation for the second point too. You should build more than a bundle of links. Content curation is about showcasing great links and adding more to them. Create a whole package presentation around the niche. Don't stop at listing sites. Write about the niche. This could be interviews with the very people who run the sites you want to list in the directory. How smart is that? Not only are you building your authority, learning more about the niche but you are far more likely to sell links (or make money from ads) if you have something people actually want and can't find elsewhere.
Source: What Makes a Good Web Directory, and Why Google Penalized Dozens of Bad Ones - Moz
- Start with a Niche - Find a topic you're seriously passionate about, from birds to routers to online clothing merchants.
- Don't Just Make a Directory - Put great content about your subject on the site: blog posts, articles, tools, resource lists, charts, diagrams, investigative journalism, etc.
- Offer to Review Sites in Your Niche - But, for goodness sake, only include them if you'd really, honestly endorse them.
- Provide a Reason Why They're Listed - Imagine a fellow hobbyist or researcher in your topic of interest in real life - if you couldn't sit down with that person at a table and show them on your laptop why you included a particular site, DON'T include it.
- Don't Offer Gimmicks or Link Juice - Offer listings on a site that real people who are really interested in your topic read and use and enjoy. If you start down the path of selling links for search engine value, you've lost your way. It can always be a secret side benefit, and plenty of folks who'll come to you for links will be thinking about it, but if you want to be truly immune to any future penalties or devaluations, you can't make it a focus.