The attached screenshot is from Quicken 2013, but I believe that it will be the same in Quicken 2010.
There is not a lot of control of font size in Quicken and it does not change everything, it is something that Quicken is not very strong in. I personally think they need to have at least one color scheme that is bolder so that the print stands out better, but alas, they don't.
I don't know what size monitor you have or the resolution that you run it at, but obviously, the bigger the monitor, the better, but running the resolution at the lower levels but at least at the Quicken system requirements minimum will also help. (1024x768 is the minimum for Quicken)
Another way of looking at the resolution issue, is that for a given monitor size, the higher resolution that you run at, the characters get smaller, so if you stick to the minimum resolution, the characters will look larger on the screen.
All of this resolution stuff is controlled in Windows and not in Quicken.
Splasher is absolutely right about being able to make the the characters appear bigger by configuring your monitor in MS Windows to use a smaller resolution. In Quicken 2013, under the "View" menu tab, there is a "Use Larger Fonts" option that can be selected. Turning that option on in the "View" dropdown list seems to increase the size of the characters in Quicken by about 50%. I am not sure if the option is available in Q2010 or not.