For the club championship:
Make sure the course is well-marked; hazard lines, GUR, etc. Give lots of thought to the setup (two days?) in terms of pin positions, etc.; don't go overboard in either direction with your setup.
If you are playing in flights, keep the handicap ranges pretty tight. Don't have a 5 and a 12 in the same flight; one or the other is going to be pissed at the end, and with good reason. Alternatively, you might consider letting players sign up for which set of tees they wish to play, with the club champion coming only from the flight that plays the back tees.
Have the pro work the first tee, going over the rules, giving out scorecards, pin sheets, etc. It's a big event, and he should be there rather than the regular starter.
Don't expect pace of play to be very good; few of your golfers play stroke play tournaments during the year. It just takes longer.
Give lots of prizes (1-2-3 Low Gross and Low Net, multiple flights, whatever). Prizes don't have to be much, but lots of people should leave feeling like they were competitive and were rewarded for doing something good.
Take pictures and publicize the results in newsletter, on the website, in emails, whatever. Make the membership feel like it is a big deal.
For the Member-Guest:
I never play in these; too much money, and too much sandbagging (or rumors of sandbagging). So no advice from me on this.