Congrats and good luck. My advice - if you want a lot of walk in customers and easy money that's just paperwork and no inventory, do $10 or $15 transfers and you'll be busy all day.
Heck, do free transfers and you'll be flooded with customers. It's simple paperwork, and will get you non-stop traffic. That's FAR less expensive than any advertising in my book. I don't know why gun shops don't understand this simple marketing concept. You're already paying the overhead of an employee to stand around. Put him to work doing paperwork, and do free transfers. The cost is near zero and it would be better than spending $1000 per month on ads.
That right there is free marketing advice from a newly minted MBA graduate with honors!
I refuse to even go into price gouging FFLs that charge more than $30. $25 is my absolute limit and I'll shop around for someone less expensive.
A local shop here just got an FFL and they do $15 transfers and stay quite busy, and they move other inventory while 2 people poke around in the store.
Have some high margin low cost stuff on display and you'll move it. Have plenty of mags and ammo in stock and have the sales person upsell them - "I see you're getting an 870. We have these accessories for it on sale... Magpul hardware, magazine tube extension, side saddle..." or "That's a nice Glock 17, we have nite sites, magazines, etc." Cleaning supplies, etc.
Also, have a professional looking website with your phone and address on every page. I don't know why this is so hard for folks to understand. I don't want to have to hunt for your address and phone number!
You can build on on wix.com easily and hosting it is about $150 a year.