I have been doing this professionally for last 12 months.
Build network, rank a site, sell whole deal or use it for own good.
You need couple things:
1. soft to manage content on blog network - schedule posts/etc/etc - trust me, you do not want to log on and configure wp-robot or any other plugin on each blog.
2. preferably a non-seo hosting that gives you good IP diversity.
In my experience though, you can easily put 2-3 sites in same niche on same IP without problems.
When building blog network, however, MAKE SURE your sites look real enough to pass manual inspection, especially, if you are planning aggressive backlink building to those blogs. That would mean that ideally you would want a professional theme, all the author/about me/privacy/contact info pages made and at least 5-6 good quality unique posts per blog. Make sure you have all the social sharing plugins and, if possible, build some social proof - fbook likes, tweets, high authority social bookmarking will surely help and attract some traffic as well.
Same goes for backlink building from those blogs. Forget everything you know about SEO, think and link from those blogs like a person that has no clue about SEO - that means do not make each post 500-700 words linking out with some keywords. Toss in posts with no links at all, toss in a good curated posts, write few unique articles, go on vacations.
There is no need to post to those blogs on a daily basis - no sane real person does (well, except for those with no life, but you get the idea). Forget about auto scraped content such as press releases/etc - you can have section of those, but that should not be the core of your site. Ideally, you want to build a 20-30 post highly themed mini-site and then move to next one leaving this one for good.
One more thing - it is worth going all those extra steps because this will be an asset you own and not someone else's blog you can nuke shit out.
Hope it helps and good luck. If you need advice about some management/automation tools, hit me up in private, wont post any links here.