This article discusses briefing the approach. It's primarily based on experience using NACO (Government) approach plates as opposed to Jeppesen, but the basics should still apply.
The approach starts when you leave the en-route structure. You may arrive via a STAR, and if so that's part of the approach briefing or you may arrive via a transition route found on the approach plate or you may be expecting vectors.
If you're familiar with the route you may know what STAR to expect, otherwise look over the options (preferably before your departure or well before your arrival) and consider what STARs you may be assigned. Review the STAR and understand what transition you'll be using, if any. Then you're ready to brief the approach.
Once you've picked up the ATIS you should be able to identify the likely approach you'll be executing. Identify where you'll be coming from on the approach plate (East, West etc.) and if you'll be flying a transition route. If you're flying a transition route identify the fixes you'll use and the equipment you'll use to navigate. If the transition requires use of a VOR and the approach is an ILS you may not want to commit the number 1 NAV to the VOR. So make a battle plan for how you'll deploy the available equipment.
Talk through how you'll assign your equipment and how it'll be programmed and program the equipment that's available.
Call out each fix, heading and altitude on the transition.
Now we can look at the approach itself. If your chart has the "briefing strip" along the top use it to make sure you understand the primary navigation aid and the inbound course.
Then, looking at the plan view describe how you'll reach the IAF, which way you'll turn and the heading you'll turn to (and if you're flying the approach as own navigation your heading will be an intercept heading). If you're going to fly the procedure turn then call out the headings outbound, the procedure turn and inbound. Identify the FAF and the final approach course.
Next, looking at the profile view call out the altitudes crossing the IAF, in the procedure turn and inbound. For an ILS note the glideslope check altitude at the outer-marker (if there is one) and then call out and step down fixes and the DA or MDA. Finally note the MAP if it's a fix.
If there is timing from the FAF to the MAP note the timing.
Finally call out at least the initial segments of the missed approach point.
Memorize the 3 M's, Minutes, Minimums and Missed Approach so there's no need to look down at the approach plate after you reach the FAF.
We can use the audio panel to run through the setup of our communication and navigation radios to ensure that each piece of equipment is setup as needed and that no piece of equipment is going unused. Finally - make sure your clock is setup and ready to start timing (crossing the IAF is no time to find out the clock need 4 button presses to get into the right mode and a reset before you can start timing).
The more of the approach you walk through before you fly it the easier the approach will be to fly when you get there. In your training you probably remember that you'd go out to your practice airport and shoot an approach and, while it may have been acceptable, you know you can do better. The next time you shoot the approach it's up to your standards. Well, talking through the approach can be your rehearsal so that when you fly the approach for the first time you can fly it perfectly.