First I make (or buy) few blogs with different niche.
Then I start earning money with:
1. Payperpost: Let's say you write 8 articles each day - 3 or 4 of them are payed. So that is $20/day or $600 each month
2. I put adsense on it and earn let's say 100$ each months (remember, you own few regularly updated blogs)
3. I sell links, I don't know how much are these worth, but if you sell 5 links on few different, regularly updated PR3 or PR4 bogs links must be worth something.
If you set yourself some targets, then just go for it. You'll find to start with you aren't earning what you hoped for, but don't let that get to you as thats normal. Just keep at it, and with a lot of hard work you will get to your targets.
Most bogs can be difficult to update, especially if you want to keep the content in them unique. You can manage 1, or ,2 or atmost3, but beyond that can leave you with real problems. You will need to buy content then. You could use RSS as many people here do though.
Still one piece of advice, do not make blogs with a primary intention of making money. That should be secondary.
I have a blog but it was not started as a way to generate money, after awhile I discovered that you can make money, and really good income if you put time into it, but I update my blog at least once per day, and I have joined ppp.
Just make sure you know to use PPP and stuff your blog needs to be live 90 days and you need like 10-20 post?? I can't wait! I should be able to start within the week. My adsense isn't doing too well. But had trouble wih my niche in the begining.