I bought a new Android tablet for my friend a few days ago. While it is a powerful and beautiful looking tablet, my friend complained that the text was way too small in the tablet. Usually, you can fix this type of problem using apps like Big Font. But these apps are also limited to increasing the text size of other apps – they cannot make the system UI font larger. For making everything a little bit larger, you have to increase the screen pixel density in your Android phone.
In order to increase the screen pixel density, you can edit the build.prop file yourself, or you can use an app called Window Manipulator that makes things a little bit easier. In either case, you must have a rooted phone to start with. If you do not know how to root your phone, then you can use Kingo Root or Root Genius.
After installing the Window Manipulator app in your Android phone, you can launch it and give the Superuser permissions. Now select the option for changing the screen pixel density and make it a little bit higher. Common screen pixel densities used by different phones and tablets are 120, 160, 213, 240, 320, 480 etc., but you can enter any screen pixel density of your choice. The changes are reflected in your device instantly. In some cases, you may have to reboot the device to see the changes.
Window Manipulator also allows you to modify the device screen size by choosing the respective option and entering the custom size of your choice, but it is really not needed for our purpose (making screen text bigger). If you do not like the changes, then you can revert to the stock settings by using the Reset density option in the app.
You can get the Window Manipulator app from http://forum.xda-developers.com/android/apps-games/root-window-manipulator-t2846784.