Reading Small voltages

I have tried various levels of gain from 100 to 10000 but still no improvement. I would also like to balance the bridge by attaching a potentiometer in parallel with one of the bridge resistors but no matter what potentiometer I use I can not get the unloaded bridge to read zero volts. As far as electrical engineers go I am on my own. I have mechanical and aerospace professors to ask questions to but no electrical.