It's easy. Don't waste money on stupid shit. If you're young which I'm assuming you are(If not let me know), you really don't have much financial responsibility. Get a summer job and work your ass off, save up some loot. That will come in handy for getting a car, skis, outerwear, whatever you need in the future. It's also a good habit to get into.
I saved around 1700 one summer just from dishwashing. Put it all into pan american silver bars and doubled it.
You don't have to sit at home and nver have fun to save money, you need to be frugal. If you go to see a movie, maybe don't go as often, don't buy an extra large soda and popcorn every time. Don't buy a bunch of candy. Don't buy shit that you don't need. If you're going to spend it, sometimes spending it on things that last for a while is a better plan. If you bought a bunch of shitty food, candy, soda, and it's gone, did that really get you anywhere? If you spend that on ski gear, or even an xbox game that you'll play for a while you would get more out of it.
Just try to cut costs. If you go to fast food spend 3 bucks instead of 10 bucks. Shit like that. You don't have to completely cut out buying shit. But If you can save a few bucks here and there it adds up fast.
Even if you don't end up a millionaire by the end it's a great habit to get into. The people that are already spending their whole pay check by midweek, before they even have financial responsibilities like rent, food, gas, insurance... are in for a rude awakening when all of the sudden they have a lot of $$$ they owe for things stacked on top.
Honestly when you're young you can save damn near 100% of your loot. I would sometimes save it all and buy something big. Buying a trampoline, a drum kit, snowboard, got me much more enjoyment than pissing it away slowly on junk food or other dumb shit.
good luck.