Fussy eater

I don’t know how to get my 1 year old to eat. He just turned 1 almost 2 weeks ago. He gets so fussy and fusses almost the whole time that he doesn’t eat at all or barely eats. Sometimes he just perfectly fine. I get so frustrated. I’ve tried like everything there is to give him and somethings he likes but he can’t just eat that all the time ya know. My mom said I was the same way I was a very picky eater and pretty much only wanted milk which he’s kind of like that to. I just want him to have his proper nutrition and have him gain a little weight because he is a small baby nothing too bad doctor says he’s healthy but a little small. I just don’t know what to do .