Do a few flights without the hood on in VMC....
Departures, Arrivals, Approaches, Vectors, Holds, etc... It gets them to relax, they can see the speed at which things REALLY happen, so there's no need to rush. I found that sometimes it helps if the student can VISUALLY put themselves into the system. Setting up approaches in the GPS, tuning the radios, getting out charts will all become second nature much sooner. Using the autopilot can help too, but its better to have them hand flying if this is early on in their training. Watching a student fall apart under the hood is not teaching, because the learning actually stopped a long time before that.
This, but first thing first.
You do not set up your cockpit while doing the approach briefing. Use the chart to set up everything how you'll like it. You do not hit a single button during the approach brief. SECOND, It is briefed in parts: freq, plan, profile, mins, missed. Third, you do NOT read THE ENTIRE CHART! You read it out how you are going to fly it. I don't care about the other IAF, I don't care about the glideslope if we're doing LOC. I don't care about the MAP for jets. Read it how you will fly it.
Ex:
We'll be flying the GPS 35L into Grand Forks international today. SCAN. GPS1 is set up for the GPS35L and is currently tracking us to the (IAF). We have Approach in Com1, Tower in Com1 stby, and ground in com2. SCAN. Once we cross (IAF) we can expect to be at 3500 and turn on course, 259 deg to (FIX). After arriving at (FIX) we'll be going to 2000 and tracking to (FIX) on 349 deg. Once we cross (FIX) we will have the gear down, flaps standby and 90 knots. SCAN. As we are tracking to RW35L we will make our descent to be at 1250' by 1.0 dme as read on GPS1. If we don't have the runway in sight by .5 dme, we will execute a missed approach. SCAN. We will take the gps out of obs mode and track our course to (FIX) climbing to 3000 feet. Once there we will hold with 5nm legs with an inbound course of 170. I expect a parallel entry. Any questions?
This walks them through what they will do, lets the SIC know what their plan is so the SIC can support and remind the PIC. The pilot should have a general idea of what they will do before you takeoff. At least for the first 5-6 lessons. They setup the cockpit how they need, they brief the approach as to how they will do it, and this gives them 2 chances to think through the approach before they fly it. The briefing is the check and balance to their setup to ensure everything is right. If they are programming things while briefing, they are doing it wrong and need to execute a hold to get some time to focus.
It is always better and faster to take your time and do it right the first time, then to rush it, mess up and do it twice. No joke, I have been in a hold for 20 minutes while a student sets up the approach, and more than a few 15min holds on stage checks where students are trying to grasp what is next. They are new, they don't have 200 approaches under their belt and sometimes they just need that time. I have never had a single student unsat for taking too long to set the approach up, but I have unsat plenty of students that rushed through and either went way past full scale or blew through their minimums. Let them learn.