Farhana,
The graphical content of your boards, as individual pieces, are graphically pleasing and clear. The overall layout of the boards does need some work. There seems to be too much information on each board. The over crowding takes away from the boards ability to effectively and clearly represent your thesis. My recommendation would be to outline your boards like you would a written paper.
What order do you want to present the information in?
What is the topic or idea for each board?
How will the boards be presented or displayed?
How will you the boards together?
Is there a clear path for the reader to follow?
There is a tendency to read from right to left and from top to bottom make sure you capitalize on this tendency.
Do the boards function without you there to explain them?
I hope these questions will help you refine your final presentation boards. Not all questions may be relevant but I hope the ones that are help you clarify areas for possible improvements. A good way to help hone in your content is to have someone outside the discipline read and ask questions about your boards. Sometimes we need that outside perspective to take a step back from our work.
Hope this helps
~Jeff