What do we mean mind control techniques?

You're going to have to go back more than a century for this. During the 1890s, Ivan Pavlov experimented with conditioned reflexes, using dogs and bells. I won't go into detail but there's a brief account of what he did at this link.

Much of what has since been dubbed "mind control" or "brain washing" has followed on from his work using techniques like hypnosis (which was developed from Mesmer's "animal magnetism" by Scottish physician James Braid) and Neuro-Linguistic Programming (NLP) which owes much of it's present effectiveness to Dr Milton Erickson, and even hallucinogenic drugs.

The KGB and the North Vietnamese were among the worst abusers of brain-washing but even their excesses paled into insignificance alongside the CIA's "MK Ultra" program of the 1950s and 1960s. I'll provide a link but unless you do some research on this yourself, you simply will not believe it. The psychologist behind the project was a folk-dancing church-goer who saw nothing wrong with what he was doing and was able to divorce his social and spiritual beliefs from the evil that was MK Ultra. Here's one link, but Google it yourself.

You may find that link unbelievable, so here's another. It's the transcript of the senate inquiry into MK Ultra led by Senator Edward Kennedy. This transcript was made available by the New York Times.