First, you need tough skin. This was a particular challenge for me since I struggle with selective mutism. On the other hand, it has been a huge boost in helping me overcome it. Second, YOU are the author and you don't have to use every suggestion people make. Example: Grandma went to the movie with me and Susie. When someone tells you that it should be 'Susie and I' they are wrong. You know your characters and where your story is heading. If you aren't sure about changing something-hold off. Give it some thought. Have a few readers read through the entire book and give their recommendations. Preferably readers who often read and enjoy your genre.
It is beneficial to receive feedback from multiple people and fun to give feedback to others. It is, however, frustrating that it takes so long to get through an entire manuscript at 5ish pages a week. This is another reason why it's good to find people who can go through it quicker and give an overall critique as well as page by page.
Most important of all-have fun! When it gets to be a chore, take a break or move on to something else. Sometimes just writing for my own enjoyment and that of my teenage daughters is the most fun of all.