So I have a premium snapchat and I offer different ways for them to sign up. I do have a monthly subscription for the people who prefer that and I have 7 day trial, 1 year and lifetime options for the people who just want to pay once and forget about it.
Unfortunately, a LOT of people get scammed with snap so it can be difficult to get buyers at first unless they trust that it's going to be worth the money. (reviews from other members help A TON)
For me, personally I post at least 5 days out of the week on my snap and I do at least 1 full cum show during that week. I offer solo and boy/girl shows and I allow screenshots. Every Friday, I do a #repostfriday where I repost the weeks snaps incase anyone missed a day. I have a public snapchat that is a different account where I add anyone from my premium who wants to be on there (that's where I post my daily ramblings and just life stuff) but I keep the premium account itself separate. Everything that I post gets put on the story and stays up for 24 hours. I don't include personal snap pics or vids. I do like to chat so I generally respond to all the people when they message me, I have around 900 premium members and only about 10% of them send me messages to chat every day, and I make it very clear that I only respond when I am on the app, at my leisure. I Have a graphic with all of my snapchat rules listed out that I send to every new member as soon as they get added, that way I know they are clear on the rules and there are no misunderstandings.
IMO, the most important thing you can do is figure out what you're going to be comfortable offering and do that. Just make sure you price it accordingly. (and I recommend pricing high enough where you can offer discounts and still make a profit)
and be CLEAR in what they will be receiving! Models offer so many different variations and if it isn't written out for them it's not really a big surprise if they expect something they are used to that you may not offer. If you're only going to be posting a few times a week, a few snaps at a time- make sure they go in knowing to expect that. People will get your premium for you not just for your naughty snaps, so whatever you choose to do they will be happy with!
Hope this helps!