How can I learn to "Use The Force"?
Not everyone can become a master like Obi-Wan or Qui-Gon in just one lifespan, but everyone can learn to use the Force and come closer towards the mastery of such renowned Jedi.
When you see Obi-Wan controlling the minds of Stormtroopers, or Yoda lifting an X-Wing Fighter, you think, "Wow!" - unaware that you too perform feats like these everyday, though not on as grand a scale.
Really, it is all a question of scale. Consider that everything you do - from breathing to blinking, to piloting a star cruiser - requires an extremely deft coordination of millions of living cells in your body. Each cell is an individual Living Force. How do you control and move all those different entities?
Call it "subconsciousness" or call it "superconsciousness", it is in fact The Force.
Oh, you say, that is all within your body. But within or without makes a difference only in your mind. When Yoda lifted the X-Wing, Luke Skywalker said, "I can't believe it." Master Yoda sagely replied, "That... is why you fail."
Every living entity has the potential to be a Jedi and use the Force in one lifespan or the next, because every living entity is the Force. Master Yoda told young Padawan Luke, "Luminous Beings are we, not this lump of flesh and bone."
How do you start learning, you ask? You must begin your Jedi Training.
What is "The Force"? (Basic)
What is "The Force"? (Detailed)