Prior to going to the NSO, try to locate the nearest NSO branch to you. A good practice is to look for 'National Statistics Office' (under 'Philippines') in your phone directories. You could also check out the online directory of NSO field offices.
Now, try to call the NSO nearest to you and ask them for their specific location.
Now get some some sleep and be at the NSO before 8 AM. Be sure to arrive at the NSO around 15 minutes before 8 AM or you'll be stuck in a very very long line. Oh and don't forget to bring your birth certificate.
Once you arrive at the NSO, present your birth certificate to the officer or guard.
You will then be asked to fill out a form. Give the accomplished form back to the guard or officer then wait for your name to be called.
Once your name is called, present a valid ID (identification card) then proceed to pay for your authenticated birth certificate. A copy of your authenticated birth certificate costs 125 pesos. You can request for more than one copy. I recommend purchasing three copies of your authenticated birth certificate. This way you would have extra copies.
Once you paid for your authenticated birth certificate, you would be given a receipt. You would notice that there is a date written on your receipt. That date is when you should come back to claim your authenticated birth certificate.
Be sure to be back on the date written on your receipt. Now give the receipt to the officer or guard. And then when your name is called, just go to the counter or window and then your authenticated birth certificate will be given to you.
That's it! I hope that this will aid you in getting your authenticated birth certificate from the NSO. Oh, and one last thing, beware of fixers!
Just a disclaimer: I am not connected to any government office so I won't be able to answer any questions that you might have regarding procedures and processes on how to procure documents such as an NBI clearance, an NSO authenticated birth certificate, and etc. All the information that I have is already presented above. The information presented in this post was gathered when I transacted with the Zamboanga city (region 9) branch/office.