You will be able to find many thesis proposal samples online and I am sure that your tutors will also have provided you with sample thesis proposals to help you. The problem is that every will be different and also unlikely to be around your specific subject or topic; so how do you use it to help you write your own proposal?
Whatever you do; never copy anything from a sample thesis proposal as that will very quickly end your academic career when it is discovered.
Sample Thesis Research Proposal
Looking at sample thesis proposals in my discipline gave me some ideas, but did not motivate me to get started. It wasn't until I found a wonderful book called The Proposal Cookbook: A Step by Step Guide to Dissertation and Thesis Proposal Writing by J. Bruce Francis, that I felt confident to begin writing my thesis proposal. This book is out of print, so I have summarized some of its suggestions for you here.