Holding clearances are complex and often arrive with short notice. The best practice is to prepare yourself BEFORE you receive the clearance. Have pen and paper ready at all times when flying IFR in busy airspace.

When the holding clearance arrives, write down the following elements in order:

Example: You receive the following clearance:

"Lufthansa six-five-two, cleared to the KAVAL fix, hold West, inbound track one-eight-zero, LEFT TURNS, expect further clearance at zero-one-four-five Zulu."

You write:

FIX: KAVAL DIRECTION: West TRACK: 180 inbound TURN: Left EFC: 0145Z

Once you have written down all elements, read back the entire clearance without pausing. This shows ATC that you have copied accurately and understand the clearance completely.