1. pack your lunch
2. cook dinner every night
3. if you smoke and drink, quit
4. don't make any big purchases in the next year (i.e. car)
5. budget yourself, and cut corners by lowering your cell phone package, your cable package, etc.
6. Do not carry an ATM card, just one credit card for emergencies. Carry only the amount of cash that you need so you won't be tempted to spend $$
7. Cut coupons...or get a food store bonus card. (The last time I went to the food store, I got only things that were "on sale" with the bonus card, My bill was $138 before the discounts and $105 after. Come on..that's good!!)
The number one thing you should do is take 20% of every single pay check and put it in a separate account. Do not carry an ATM card associated with that account. Vow not to touch except for wedding things!!!
If you make $15/hour (hopefully you make more if you are planning on getting married...but I'm going with worse case scenario here), you make $31,200. If you take home 70% of that, it's $21,840. 20% of that is $4,368 a year. That's $368 a month. If you get married in 18 months, you can potentially save $6624 just on your own. (that's if you make roughly $30K a year).
It's very possible. But you need to be strict with your spending. Good Luck!