Two mindsets, by this what I mean is that there are one of two ways to motivate someone. Both of these techniques contrast like day and night.
One is to tell then that they can’t do something; or tell them that they are really bad at doing it. This will in turn set off their ‘stubborn’ part of the brain (I’m no doctor or psychologist, so simple terminology :P) They will be inspired to prove you wrong and smash you to the ground. This will in turn push them to become better at whatever they do.
The second method may seem like ‘the wuss method’ relative to the first one; it’s a less brutal method. If someone is either good or bad at doing something then just tell them that they are good (or even better tell them that you look up to them and want to get to their stage one day). They will be encouraged to get better because that’s the natural instinct of the human brain. If a person is good at something it may seem easy to them mainly because they enjoy doing it; therefore they do what they are good at because it’s simply easy. :))
These are all the techniques I am aware of, maybe there are more or extended versions of these. It varies from person to person and maybe to a specific situation. Personally for me the second method is the most encouraging and it definitely does work.