1) In the process of writing don't read and re-read what you've just written on the page. Simply write. The reading can come later--(see step 5)--assuming you've saved your work on a flash drive in the unlikely but altogether possible event your computer crashes.
2) Save your work on flash drive or back-up system every writing day.
3) Don't read your work to other people (or give it to them to read) during the early stages. It's none of their business and they probably don't want to hear it anyway. It's your piece -- your voice. Write until you're convinced it is where it needs to be, then hand it over to a trusted reader and brace yourself.
4) Interject an element of hilarity into your mindset. The sun will come up tomorrow, even if you don't get that troublesome sentence just the way you want it. Throw anything out there. You can always reign in your over-the-top sentimentality during the later stages.
5. If you don't feel like writing, read what you've already written. Then, soon, you'll find yourself writing again.