The easiest way to do this is to take as much as you’re allowed with you. The amount does vary by company so read the fine print. Most cruise lines will typically allow travelers to bring one or two bottles of wine. Or you can drag along soda or beer, if that’s more your speed. The restrictions tend to apply more to alcoholic beverages than soft or sports drinks. Therefore, you might be able to keep bringing more on as your supply runs out. Just keep in mind that some cruise lines won’t allow this.
As was pointed out here, using flavored powder for the complimentary water onboard is another good way to get around the bizarre drink regulations. You can even take your preferred brands of coffee, hot chocolate, and tea to brew up the drink of your choice. All the same, most of these drinks are available for free so there’s really no need to bother, unless you have very specific beverage preferences.
Another good idea is to buy a bottle of wine and have it marked with your room number so that you can drink the rest of it later.
You might even want to look at getting a beverage card that allows you to pay a flat rate per day instead of paying for them individually. However, do the math to make sure that it will save you money. It often doesn’t. This can likewise be the case with the daily drink specials, which might not actually be any cheaper than they were originally.