1) Criticism will happen. Not everyone will like your book/story. That's good. That is the very definition of an audience. Expecting criticism makes dealing with it easier. However, ignoring criticism is not always a good idea, as it helps us see our creativity from another perspective, often times helping us improve it.
2) Keep writing, don't give up after one try, and just try to write a little each day. Just like eating an elephant, every bite matters. Also don't eat an elephant, that will likely delay your writing.