Pay the taxes challenge

Now that my job is currently not offering overtime, I've been trying to think of ways to make extra money. But then I realized I'm actually making some extra money already, but it's just not that much. I want to start a challenge to myself for the second half of the year starting July 1st: pay for our income taxes without using money from our "day jobs". My estimation of our taxes is $700.

Here are some of my other sources of income. This income varies a lot each month and some months I don't earn anything from them.

(Very) Part-time job:
A former employer has me do some work for them on an as-needed basis from home. It usually ranges between 0 and 2 hours a week (usually closer to 0 than 2) and they pay me $10.50/hr. It seems they are the busiest during the Spring, and the second half of the year is usually a little slower than the first half.

Babysitting:
My sister needs someone to babysit her daughter every once in a while. She pays me $5/hr. However, she recently moved about an hour's drive away, so she probably will not ask me to babysit nearly as often.

Blogging:
I have something like 6 or 7 blogs that I recently monetized with advertising and affiliate links to products from Amazon (I get paid a percentage of the money spent when people buy using my referral link). However, I'm really only making money on one of the blogs. It's not this one in case you're wondering, it's one that's been around for over 3 years. The rest of my blogs are all less than a year old and account for maybe 0.5% of the money I've made blogging.

Ebay:
Once in a while I sell items on Ebay. It's garage sale season, so I might be able to find some items for cheap that I could sell for a profit on Ebay.

So it will be a challenge to make $700 with just these.  I would like to find new ways to making money and while increasing the money I make on my current sources of income as well.