To begin with, if you have to make a research proposal, the first and definitely most necessary thing to do is to find a good idea for it. The point is that your idea has to be interesting for you first of all, so think thoroughly of this issue. If writing a paper makes you boring then you are not going to succeed in it. Your idea has to inspire you, make sense to you and only if it does you will write a good paper.
Research proposal ideas don’t actually appear from nowhere. They have to grow in your mind as a result of hard work, experience and observation. In some cases, students get ideas from attending scientific conferences, seminars, workshops, reading appropriate literature, including scientific journals and blogs, watching movies and TV shows which are somehow related to their area of interest.
Also, you can look for research proposal ideas while communicating on scientific forums, where you may get acquainted with interesting people, like professors or other students working on different kinds of research like you. Anyway, communicating will open your mind and fill it with new fresh thoughts.