Engine bay cleaning
Chances are, you will have a quite lot of mud, sand and salt in the engine bay after any trip off road. It's always a good idea to quickly clean all this up so it doesn't sit inside the engine bay and cause issues like foul smells, or get in the way when you're trying to swing a spanner. It's best to do this before the rest of the car, to avoid water drying on the rest of the paintwork.
Grab some Down & Dirty, a Nuts and Guts or Big Boy Brett brush, a couple Dirty Deeds cloths and a battery powered portable blower if you have one. Make sure the engine and any rubber hoses are cool to the touch before you start.
Give the engine a good rinsing, being careful to avoid intakes, electrics, and any other locations you don't want water getting into. Some manufacturers have exposed ECUs under the windscreen area, so do your best to not force water in here (angle the hose towards the front of the car where possible).
Break the engine bay up into quarters and work on one section at a time, to ensure you get a thorough clean done.
Dampen your Dirty Deeds cloth and add a few spray of Down & Dirty onto it. Spray Down & Dirty directly onto the engine bay on dirty areas. Immediately agitate with one of your bushes, and wipe over any parts that cannot be agitated with the Dirty Deeds cloth. Rinse thoroughly with low pressure from the hose, taking care around any electrical components, air intakes, alternator, fuse box etc.
After rinsing, blow any remaining water out of nooks and crannies with the blower, then dry the rest of the engine bay down with a clean and dry Dirty Deeds cloth.