Yes, avoid direct high-pressure spray onto the electrical components, and you may want to put plastic bags over the parts like distributor, brake reservoir, etc.

Also, of course, try not to force water through the air cleaners...prety much common sense stuff. :-)

I haven't had an awful lot of luck with citrus degreasers on extemely dirty engines. I usually start with full-strength Simple Green on a hot (warm) engine and let it sit a few hours to loosen the crud. Follow with a stiff brush, scraper, whatever you may need to pry oily clods loose. I like those nylon/soap kitchen scrubbers for fine wrok, and I use a cleaner-soaked rag to finish up.

Once the engine is clean, it's easy to keep it that way by wiping it down whenever you have the hood open or are washing the rest of the car.

Try not to get to be like me...I have to jack mine up and wash/wax the bottom side too! *sigh*

A detail shop will do your engine bay for anywhere from $50-$75.

They use a protectant on the rubber parts (like 303 Aerospace) and usually try to put a coat of wax onto the areas that show - it helps keep things cleaner.

Don't forget the underside of the hood. Nothing like showing off your engine with oil and dirt on the hood!

Have fun!