I am not any kind of parenting expert. But I am asked for parenting advice surprisingly often, especially by fathers and especially by people expecting their first child. Because it's more efficient to write one blog post than many emails, and because I really like talking about parenting and welcome any comments about my views, here it is:
When you don't know what to do and need a heuristic, consider using this one: make the choice that is less likely to lead to a big mistake or catastrophe. (If you prefer: assign each possible outcome one of two utility values, with one of the values corresponding to "non-catastrophic" and the other corresponding to "catastrophic." Then assign probabilities and act accordingly.)
Consider reallocating a little bit of the energy and thought you give to your child's eating to your child's sleep. Food is important, but so is sleep, a domain in which investments of planning and energy can pay off handsomely.
You're likely to get a lot of advice from other parents. A lot of these parents are (full of joy but also) worried, regretful, insecure, and so on. Try to be kind, even when they offend you. And remember that worry, regret, and so on make it even harder than usual to distinguish one's particular experience from the general situation. So: other parents' stories are a great way to learn what's possible but a very bad way to learn what's probable.
You're likely to deal with many medical professionals. Perhaps not all of them will guide you in ways that are both medically justified and in line with your values. (Pregnancy, childbirth, and pediatrics put you in the path of a lot of job titles. People with those jobs have varied training and value systems.) You and your family should prepare to advocate for each other.
They're underrated! Many great parents became great parents without the help of any books--and I mean that fully sincerely. But I have found books to be invaluable. If you like to learn by reading, don't be dissuaded by the fact that parenting books are in certain circles unfashionable.
I'm struck by how many subdomains of parenting have a single book I vastly prefer. (Two conjectures: I haven't read widely enough or the genre admits diverse styles many of which I strongly disprefer.) Some of my favorites:
Precious Little Sleep, by Alexis Dubief, for sleep. When people ask for a single book recommendation, this is it. (Dubief is a finance whiz who happened to learn all about sleep for young people and then made a career out of it, much to the world's benefit.) The Happy Sleeper is also worth considering.
Bringing up Bébé, by Pamela Druckerman, for the importance of daily structure and emphasis on the fact that aspects of parenting can seem biologically necessary when they are in fact culturally contingent. (This book is controversial, and I'm not asserting that everything Druckerman says about French culture or good parenting is correct. For me it was a useful case study and a valuable tool for seeing Anglo dogmas about parenting for what they are.)
Oh, Crap!, by Jamie Glowacki, for potty training. Not for the faint of heart, but neither is parenting. Review here.
Expecting Better, Emily Oster. Not dissimilar to Precious Little Sleep in being (what started as) a side intellectual output of an expert information-synthesizer in a competitive domain: Oster is an economics professor at Brown. A useful synthesis of what science we know about pregnancy and infancy. Cribsheet and The Family Firm (its sequels) are great, too. I am often grateful that Emily Oster had a kid just a bit before I did, and I hope she keeps writing books about every parenting stage I'm about to get to.
No Bad Kids: Toddler Discipline Without Shame, Janet Lansbury. My favorite book about toddler parenting. There's lots of situation-specific advice, and it's all grounded in a plausible, useful, and non-obvious theory of toddler psychology.