Most of the people that are presently sitting in first class may not necessarily have paid for their ticket but instead they received a free upgrade from coach.
The first way to do this is to pay for an upgrade and when you do this you have two choices.
Most of the airlines make it possible for customers to upgrade their seats to first class, and if you are a person who travels a lot you will know that first class can be filled very quickly so it is best if you upgrade your seat in advance.
There are two ways to do this either by internet or talking to a representative over the phone, you also have the option to upgrade your ticket at the airport.
When you check in at the airport ask them if there are first class upgrades available for sale, and these are usually very expensive at the airport and at the last minute.
When you are ready to pay for your upgrade you can do so by credit or debit card and also with your frequent flyer miles to cover a sum of the cost if you are a devoted flyer.
Although it seems to be tedious you will save on the price of your first class seat.
Even if you are not willing to pay for the upgrade just ask, as sometimes it depends on who you ask at what particular time.
For example if you ask the representatives at the front desk you will have to pay them.