You're not trying to memorise the approach when you brief it. Your pre-approach brief is to make sure you have the correct approach (very easy to get either the approach *or* the location wrong), configure the aircraft/avionics, catch any traps, and give you a general overview of the procedure.
Things in the brief to cover:
* Correct runway, approach & location. If multi-crew then compare dates too, to make sure everyone is following the same procedure.
* Avionics tuned, ident & set. Pre-tune as much as you can.
* Plan view: get a general idea of your entry and approach layout eg left procedure turn prior to a right teardrop/break towards the aid circling.
* Profile view: Descent limitations
* Minima
* Where to expect the runway/how you'll break for a circling procedure. Don't forget circling limitations...
* Missed approach overview.
* Notes/precautions/limitations.
Not everything on the page will apply to you. Part of the brief is to discriminate.
One way to keep your mind focused on the next most important thing during an approach or hold is to continually self brief the most important info. I use & teach 'T.A.A.': Track Altitude Aid.
Track: Next direction of turn, HDG or Tr. to intercept, set HDG bug/OBS if possible eg "Next: L teardrop to track 180", "R turn outbound Head 235 1 min",
Note: 'tracks' are to be intercepted. Headings to be held +/- drift allowance
Altitude: Next target altitude + next altitude limit eg "2000, not below 2300 til 5 DME", "MDA 550, missed climb 3000"
Aid: Flags away (VOR/ILS) / Ident OK (NDB) + set/tuned if a change is necessary / approach mode incl. WAAS if GPS. Of course, given enough boxes then you'd make sure these were all set prior to commencing the approach eg "Flags away", "ident OK"
This would be done as soon as you've got yourself established on each leg to prepare for the *next* leg. As soon as you have the current leg working OK (or is trending that way) then it's time to think of the next leg.