Can I learn to control my dreams that show the future?

that's the most strange thing i've ever heard. only someone with same ability can help you. what's the use of someone telling you " you have a gift". search for people who had same experience.

first each night before you go to bed remind yourself that it's your dream and you control it. and all people in the dreams are at your mercy, if they dont do what you say kill them. lol. anyway you need to stay calm while in the dream, and if you want to wake up, try rolling your eyes while there closed it's hard but it gets you out.

Well you could try learning how to Lucid dream, but i'm not sure if you'd still be able to "see the future".

I have this too. It is not a gift, it's where you randomly picture something then you see it. DEJA VU. It's freaky too, happens to lots of people. You are not special. It happened with me seeing a scratch sheet with specific drawings on it. Saw it a week later. Creepy. But anyway, coincidence, you cannot control it unless you are weird and believe in fortune telling. What happens is, you dream like 10 "scenes" or instances a night, so using odds, eventually one will happen. Most commonly, it's something like seeing a certain picture in your head.