Grant says to "don't forget that it's normal" meaning everyone feels the same fear and doubt. If others can feel this and still move forward, so can you. Many times people see the successful and and just assume they don't have doubts or fears but this just isn't true. The successful have just learned how to deal with and work through the wrong emotions.
Grant also says to "fill your calendar" meaning stay busy. The idle mind is the mind that has time to think up all the problems that can happen. A busy mind is experiencing more success and therefore fewer doubts. Stay busy and do more than is expected.
These are just two of Grant's points. Click the link above and take some time to read what Grant has to say. Then push through the fear and the doubt and take big action to achieve big results.