Find a reason to "do something special" with a select group of friends, based off of an extraordinary event. This could range from "It smells like Fall!" to "She cut her own bangs like a day after they broke up. Lets have a girls thing". In many cases, the "special event" is a couple's new dietary restriction. If invited to an alkaline-heavy dinner that is glucose free and vegan, decline. If you are a member of said couple, shut the fuck up about your life because everyone knows you sit at your fridge with a roll of cookie dough after serving us all your quinoa and granite cake flakes.
Involve a trusted two to ten people to begin planning. First on the agenda is guest list. Once your planning committee has spent an hour discussing plus ones, decide to discuss venue first, which will help determine the guest list based on the logistics of the space. Great way to divert any sufferers of FOMO who find out they didn't make the cut. It's not them, its the limited garden seating on the patio.
Discuss amongst yourselves the venue options in groups of two or three. Each subgroup should think of two or three potential guests who absolutely must be invited. These mandatory invites extend most frequently to pushy friends who aren't afraid to leave a "where was my invite, hahah...." comment on an Instagram from dinner.
Return to a full group discussion. Agree on the general number of guests, plus five for anyone who you might have forgotten and has potential to be offended in an overt, uncomfortable way. As a panting, exhausted group, decide on the all you can eat and drink sushi/sake restaurant in midtown to accomodate growing number of those involved. Delirious, wild-eyed and relieved, send out mass email to the twenty or so friends who you could not afford not to invite.
Recieve barrage of email responses, ranging from "a friend mentioned she got sick from there, I'm not sure" to "OMG can we PLZ not go to that place". A couple "sure!"'s from the guests who are planning on pulling out last minute anyway. Re-assess entire plan with your most loyal planning committee member. Shit talk every single person who had some complaint over this extremely thought out plan. Vow to disinvite them if you scrap this plan and go for something smaller and simpler.
Disassemble original plan. Send out passive aggressive email to original recipients, requesting that they "bear with you, as you want to accommodate everyone". Draft second email detailing smaller dinner at a more expensive, less DIY-y restaurant. Only send to original planning committee, those who sent the very appreciated "sure!" and everyone who ignored the first email without responding.
Receive the same number of "sure!"s. A few "can't afford to go out for dinner, will meet up with you guys after for drinks!"s. Anxiously await the pending date, with an unshakeable sense of dread. Throughout the mornign and afternoon on the Big Day, recieve intermittent cancellations from all those who answered "Sure!" so confidently, and so early on.
Call the restaurant to change your reservation to a smaller number. Enjoy your expensive dinner with the six friends who you had tried to make a big dinner plan with.