I spent a couple months researching the exact same thing. Initial investment can be quite high.
Have plenty of cash on hand. At least enough to sustain you and the business through the first 18, and preferably 24, months.
Pick you're clientele and plan inventory accordingly. People think liquor stores are all the same, but that couldn't be farther from the truth. If you want to cater to the $10 30-pack crowd, there's not much reason to stock 20 cases of $50 a bottle French wine. Same for liquor. Do you want to be the go to place for hard to find, ultra premium aged rum? You can't be all things to all people. Know your target customer and what they want.
Check liquor, beer and wine laws in your areas. There's some weird laws out there. Don't assume they're straight forward, cuz they rarely are. There's usually a substantial number of hoops to jump through to get a license. Can you pass a serious background check? I'm talking about one done by the FBI? Even misdemeanors can disqualify u in my area.
Have you written out a business plan? Looked at real estate? Come up with any preliminary costs? Know where the money will come from? Applied for a business loan before? Know how to incorporate or file an LLC?
Explore tax laws related to liquor stores. There's a ton of them. According to my states laws, liquor stores are not legally allowed to lose money in a fiscal year, like other businesses are allowed to. You legally have to turn a profit or they WILL shut you down. That may have even been a federal law, can't remember off the top of my head.
Talk to a lawyer that has worked for a liquor store before, they can fill you in on a lot of little things that you never would have thought about.
Your employees WILL STEAL FROM YOU. it's a guarantee. I talked to over a dozen liquor store owners, from high end wine and spirits importers to beer stores and everything in between, and this was one of the biggest things they deal with. You have to plan for and accept a certain amount of it, while putting systems in place to keep it at a minimum. A little of it is to be expected, but if you can't keep it in check, they'll bleed you dry in a short time.
I'm still in the preliminary stages of planning, and not sure whether I'm going to go through with it. If done properly, a liquor store can make you a significant income. When done really well, they're pretty damn close to printing money. But, there's a lot of regulations and challenges to follow. Mess up and sell to a minor and you can be hurting quick, fast and in a hurry. it's got all the standard challenges of any other retail business, with a bunch more added on top. Good luck.