What is the best strategy to follow now?

We are a startup and our project consists of 4-5 sections, each one will have several standard and advanced features. What we will seek in the future is a funding.

We are currently developing our first section and we added to it the standard and a plus of features. Of course there will be many advanced features to add to it in the near future.

However I thought that before continue adding advanced features to it and spend about one month, that would be better to start our new sections.

Finally when all sections are completed to a standard number features, we will spend some time to add advanced tasks to them and seek funding.

How do you find my thought of finishing all the sections at first, and then create advanced features to it?

The best strategy to follow right now is to foucs first on the critical essential product that is needed by your intial customers.

They don't need 4-5 sections. What one section is at the core of your initial offering?
They don't need a huge feature list -- they need the list of features that allow them to meet their immediate need. What is that list?

Get that section with those feature(s) into the market -- and then lay out a plan for future improvement, development, sections and features in the context of direct communication and prioritization with the customers.

There are a couple things that will make this "best strategy" work for you:

1. Customers are the people who will pay your bills. What is your business model? Who will pay the bills? What are they going to pay for?
2. The essential function/feature/service is the minimum needed. This will be different based on your market and industry. If you are in a regulated industry - minimum means something different than a web portal of pets supplies.
3. Understanding your market sufficiently to know the critical section/features is important -- and know that when you actually start engaging with the customers this will change is essential.

Happy entrepreneuring!

You make no mention of users and customers. Find those first. Build the minium solution that they need. Have them test what you build, one iteration at a time. Get feedback, keep iterating.