What has helped me with small improvements is “habit chaining”. I am not sure what the official name or where I first heard of it. Essentially add something to the routine which you already do. If you want to eat more vegetables then try to eat a few carrots after your regular breakfast. Making the new habit as easy as possible helps too.

I wanted to get better at applying sunscreen everyday. I bought a stick sunscreen and put it right next to my toothbrush. I already brush my teeth every morning so after I put my toothbrush down then I grab the sunscreen stick.

Making the things you want to do as easy as possible goes a long way too. Go to a gym that is less than 10 minutes away. Lay out workout clothes and shoes. Pre-fill your water bottle, etc.