On raising children... the two most common mistakes I see parents make in raising kids are (1) over-indulgence and (2) not giving them enough of your quality time.
On overindulgence... kids need to experience optimal frustration. That is, they need to experience enough setbacks in life to learn frustration tolerance, persistence in the midst of setbacks without losing hope, and the value of sustained self-discipline to realize important, larger goals in life. Optimal frustration also teaches them that things simply won't come their way merely because they wish for them. They will also learn that even with diligent effort, sweat and toil, good outcomes are not automatically guaranteed. None of us is automatically entitled to good things merely because we wish for them.
On giving kids enough of your quality time... no other single parental action will fuel your children's healthy self-esteem more than giving them enough of your time, focused on meeting their needs rather than your own. Tuning into them and spending time with them communicates that you value them. Follow their lead, offer them the opportunity to choose among different choices (all of which you can live with).