It's still a village. That's the whole point. While the rest of Paris is grand, axial, planned by Haussmann, Montmartre is medieval - narrow streets, hidden squares, vineyards, windmills, staircases that go nowhere. Until 1860 it wasn't even part of Paris. You can still feel that.
The tourists are concentrated. They all do the same loop: funicular up, Sacré-Coeur, Place du Tertre, photo on the steps, back down. About 80% of Montmartre's visitors never leave that 200-metre square. The other 80% of the hill is where the actual neighbourhood lives.
Go early. Sacré-Coeur opens at 6:30am. The dome view at sunrise is better than the dome view ever, and you'll share it with maybe a dozen other people. By 11am the same view comes with 2,000 strangers. Make the choice that fits your life, but know the tradeoff.
The food is better than it should be. Montmartre is touristy enough that you'd expect every restaurant to be a trap. Some are. The Rue des Abbesses and the Rue Lepic both have honest neighbourhood places - small, family-run, no English menus. The bakeries are excellent because the locals would riot otherwise.