This is a hard lesson to learn. You may know that you're idea is the most novel and best possible approach, but somehow you may not be able to attract an investor's attention or pocketbook.
Remember that investors are not evaluating the quality of the science behind your idea. They have specific criteria for investments in their portfolio and they are looking at more than just your idea, your team, or your business model Before you go out on the road, accept that you will be told "No" more times and "Yes." But, if you've done your homework and have worked diligently through this book, then you should have the confidence to persevere.
You will be told "No" more times than "Yes."