This is easier said than done, but is one of the most effective ways of generating traffic to your site. Whatever niche you are in, unless you yourself are an expert, getting one to write articles for you is a good idea. Of course, not many experts will actually consent to write anything for you, which is
where the previous point comes in. Most of these experts would be high standing members of the community and as long as you lay the groundwork properly and get connected, they are sure to notice you. Over time you can approach them about writing something for you, and even if they decline, you've not lost anything by asking. By becoming a respected member in the community you will just be making it that much harder for them to refuse you when you do ask.
This is not something that you can do a couple of weeks after you start, or even a couple of months after you do. It takes time to earn a name, and even if you are not considered an expert in the field, as long as you make sure that you are a respected member in the community you are to the good.
For example, if you want to start a website that recommends/sells software, make sure that you join a community where such software is discussed. Join as many as you can, and make sure that you
participate. Help out others who ask for help and if you do this long enough it is the best way to get noticed. If you offer your time and expertise for free not only will those you helped directly come to your site the next time they want something, other members in your community will also link to your articles. Over time, some of them may even start recommending that their visitors visit your site. Helping others very rarely does not pay; it just takes time for you to see the results.