Throw out as much apps as possible, use as less features as possible (no phone calls, no messaging), overclock your CPU and GPU, use as less RAM as possible, switch to CyanogenMod or any other close-to-vanilla Android ROM.
What do you care more about? Some random numbers from benchmarks or the real performance and amount of features during daily usage?
Benchmarks only give pure performance rating based on some random calculations. It gives no overview about how good the phone performs during daily usage. The number does not show you anything. A phone with extremely low benchmark score can work perfectly with no lag in the UI during daily usage, whereas phone with high benchmark score can be laggy and stuttering.