The photographers search is a meeting point without intermediaries between photographer and client.
With your Pro account, you'll be able to make your professional profile stand out by appearing amongst the first search results. Get better visibility, in turn increasing the chances of someone hiring you.
The more details you add to your portfolio, the better. Customers need you to give them a glimpse into your trustworthiness. Remember to add images related with the services you offer. Also, remember that it's not only about quantity but also quality.