This is kind of like feeding a baby.  At first the baby will not tell you exactly what they want.  In fact, the baby may not tell you what they want for months.  However, when they get excited while they are eating certain foods then you know they like that food.  The tricky part is that if you only feed the baby the one food that they like, eventually they will get tired of that food and stop eating it.  So you have to factor in that they will want different foods.  You ask your family and friends and they give you their advice but they really don't know what will work for your baby.  So you do your own research and feed the baby what you know is good for them.  Another tricky part is that just because the baby food is good for the baby doesn't mean it is what the baby will eat.   It is very frustrating.

Another option is to pay a baby dietician to come over and tell you what to feed the baby and the dietician will even feed the baby for you.  It costs a lot more than you doing it yourself because you not only pay the dietician but you also have to buy the food for the baby.  The upside is the baby is eating nutritional food that they like to eat within the week.  You will also have to continue to pay the dietician every month as tastes change and the nutritional needs of the baby changes over time.