One of the things I like to tell new job board entrepreneurs is to try and buy an existing job board instead of building from scratch. You can do this a couple of ways.
1. Look on flippa.com for “used” job board.
2. Google the niche you want to enter and try to buy a site that is already indexed by google. You can usually find one on page 3 or 4 and offer them a few thousand to sell to you.
In case you cant buy one here is one site to get some good job board names.