The simplest way is to wean your guests off the old regulars is to take them off the list… EVERY one knows a mojito and cosmo and if they look through your menu and spot that they get lazy and order it. Trsut me I still go through bags of mint making Mojitos even if its not listed.
If you are confident in your staff you can rely on them to sell any classic verbally.
(Who realy walks in a bar without a clue, and looks in the menu thinking hmm that negroni looks nice…)
Placing on your menu makes a great difference too. Place the ones you want to push on the front page, 1st on the list or create a seperate section called seasonal drinks.
Make it easier for your guests to read by starting a description with the base spirit, as and they can go to the spirits they like. I and my guests go to a bar to relax NOT to do an essay on all the drinks in the world.
Mention the way its served or the glass in every drink; Straight up, Long, on the rocks. It really makes a difference to many people.
In the end of the day its the staff that sell it, make it and recommend it. Ask them, see what they say. Do they like it? Do they believe in it? Would they change it? You have to sell it to them first.
Hope this helps.