With Rooted Devices it is possible to alter the LCD density of the display. It is a simple hack or trick what ever you say but it involve editing certain system files.In most cases it is fine working but i still advice you to backup your rom before proceeding.
1. Install Root Explorer : There are many alternatives to alter LCD density but my choice is 'Root Explorer' as this evolves manually editing the system files, a file browser application with root access is required.
2.System Files: Open 'Root Explorer'. If a superuser access granted request pops up then allow it. Scroll down the file list and click on the System. In the next screen tap Mount R/W button located at the top then long press on the build.prop file.
3.Editing build.prop file: At the bottom of the context menu click on 'Open in Text Editor'. In the editable text file locate the line 'ro.sf.lcd_density'
4.Editing Density: Make a note of the current number and replace with a lower number. For example if it is written ro.sf.lcd_density=240 then change the number lower than this like 200( ro.sf.lcd_density=200). Some phones may start to struggle with settings lower than 200.
5.Saving the changes: Press Menu>Save Changes Root. Explorer will backup the original file while saving the modified version.The system changes need to be consolidated via Rom Manager. If you dont have it, go to Play Store and install it.
6.Fix Permissions: Open Rom Manager and select the Fix Permissions from the main menu. This process is automatic but can take upto five minutes. Once the process is finished you will be asked to reboot the device.
7.Changes in screen: Reboot the device, it may take time while the device reboots. Once the device reboots you will notice the difference in webpages,menu,icons,text etc. This things will appear sharper.
8.Tweak if needed: If some applications doesn't like your new tweaks then try installing 'Spare Parts' and untick 'Compatibility Mode'. If you wish to get back your original changes then again follow the steps 2-7. But enter the original value in the ro.sf.lcd_density line.
9.Alternatives: If manually changing the resolution setting isn't your thing then there are apps in the market like 'LCDDensity for Root' which can automatically do the work for you. But results may vary.
Caution: There are caveats to bear in mind. Play Store may refuse to install apps due to compatibility issues. Also try to stick to vanilla (AOSP) Android Roms, other variants of android may cause some issues.
For any kind of question please comment below.