You can find a lots of papers on that topic from IEEExplorer. Some of the techniques used including bulk-bias transistors, current bulk-driven transistors, level-shifting etc.
You can start designing using bulk driven devices. Also, you can go for circuits which are pseudo differential. Always try to avoid devices which are diode connected. One good way fo designing is to do a differential circuit because you can be benefitted by double the swing.
Good places to look for are Dr. Sanchez's website amsc.tamu.edu and Dr. Tsvidis' website in Columbia. They are pioneers in Low Voltage design