If you already decided you want to get married, then I congratulate you! However if you don’t have enough money just yet or even if your not sure if they are “the one,” but you want to start saving, you can start simply by getting a jar and start adding your spare change to it every day when you get enough to fill the jar move it to a savings account then when you have enough to open an account you could move it to a mutual fund account or a short term CD. Make sure you do not roll this in with your retirement account because you will want to be able to access this account easily when you need it. Don’t forget to keep adding to it. The younger you are when you start saving the easier it will be so even if you are not ready to commit yet you may want to start saving!
The jar method works pretty good because then you can see easily your progress and that can give you more incentive to save. Also this way it keeps you from spending that money on other more frivolous things and can help bring you closer as a couple to be working toward a common goal.
If you are both working on it together you can come up with fun ideas you could do together to make side money. This can be fun and bring you closer together as a couple.