[Help] How should a beginner woodworker finish out a sycamore coffee table?

(I asked first in r/DIY but they weren't too helpful) First ever furniture project. I've been constructing a coffee table using slab of sycamore (Pics) as the tabletop. It already has 3 coats of teak oil on it and I'm wondering if it needs anything more done to it before it can handle coffee mugs and the ilk or if it is good to go. It's already been gone over with some 300 sandpaper but I'm unsure how to get it to an even smoother finish. Any tips or tricks for a beginner would be appreciated, thanks!