I've been using this new app called Resy to book my fine dining here in Los Angeles.
Resy covers the chicest restaurants and making a reservation is a cinch. I booked a meal for my mum's birthday at Terrine in Beverly Grove and everything from start to finish, from booking to meal, was incredible. Terrine actually didn't answer their phone the couple times I called to try and reserve a table, so Resy really saved my ass on this one. The French-inspired meal itself was an absolute delight and the service was impeccable, so the reservation process was a non-issue. 10/10 would recommend using Resy to book your dinner--you should try Terrine for your first reservation too!