My wife and I have found the best place to start is by finding what I call "unneeded calories". We all have foods that are really important to us and would be really hard to give up, but we also have so many calories that we eat that don't add any happiness to our lives it's just habit. For me it was pop and bread. Diet pop or seltzers are perfectly fine for me, and I like lettuce wraps just as much as sandwiches. So switching those things out isn't even a diet for me. Like it doesn't impact my happiness whatsoever and therefore it doesn't mentally tax me. My wife however loves bread so cutting that out would be massively difficult. She started with other things that were "unneeded" in her diet. It's a great starting point in my opinion.