Get the gear.
Protection for your passenger is paramount. For us this meant full-face helmets, jackets and pants with armor, gloves and good boots. If we took a spill I wanted my wife to be protected as well as or better than I was. We also wanted good conspicuity-bright colors with reflective materials. Because styles and options have improved immensely over the years (especially for women), there's plenty of gear to choose from that's protective and looks great, too.
Before even leaving the driveway we took time to explain motorcycling basics. What moves, what's hot, where to hold on and what not to touch or step on-ever! We also practiced getting on and off the bike. I asked that my wife tap my shoulder and get an acknowledgement before climbing on, then put her left hand on my shoulder and left foot on the passenger footpeg and swing onto the seat. "Try not to use my upper body to pull yourself on," I told her. "Once you're on, don't get off until the pilot says OK." (Nothing tips over an 800-pound touring bike faster than a passenger who bails before you're set.) "When you're ready to get off, reverse the procedure-tap my shoulder for acknowledgment that I'm ready for the dismount."
I also made sure my wife knew about the motorcycle's movements: "The bike will lean in turns and that's OK. Don't try to compensate-just sit naturally. Look over my shoulder and through the turns; otherwise you will be staring at the back of my helmet the entire trip. It's OK to semi-stand on the pegs to raise yourself slightly over bumps. If you need to hang on make sure you grab my waist, not my shoulders or arms."
Get your signals straight.
To ease on-bike communication we developed body signals. If my wife squeezed me with her legs, it meant "I don't like what you're doing" or "You're going too fast." Her thumb pointed down to the road signaled, "I need a break/want to use the restroom." Tapping my shoulder and shaking her fist was a sign for "Something is wrong." We also established pi - -passenger signals. If I tapped her leg, then pointed straight up and twirled my finger, it indicated I was going to accelerate or some other "hold on" maneuver. Of course the gesture of just patting her leg meant "I'm glad you're along." To solidify communications we mounted Bluetooth intercom units on our helmets. They're easily installed and removed, and being able to chit-chat really added to the experience.
Dress the part.
Because this ride was during the heat of summer we picked mesh jackets and pants for our passengers to provide protection while keeping them cool. And instead of our usual full-face helmets we opted for flip-ups for their convenience; after all, we'd be sipping drinks and discussing the ride at stops. The current modulars are almost as quiet as full-face units and offer the comfort of a helmet without sacrificing (too much) safety.
Rig your ride.
A decent passenger seat and backrest help. In anticipation of my wife joining me on trips I traded in my solo-seat cruiser a couple of years ago for its touring counterpart, with a comfy back seat and a rear trunk with integrated passenger back and armrests. For her it's like our La-Z-Boy at home!
Check Mother Nature.
While that usually means packing rain gear, preparing for heat is equally important. Mesh gear can keep you cool, but the extra airflow evaporates perspiration, which can dehydrate you. My wife kept a fanny pack around her waist complete with water bottle and drinking tube so she could easily sip while en route. The pack also kept necessities like sunglasses and lip balm accessible while riding.
Passenger or not, some things are always the pilot's responsibility. One of these is to be smooth. This means smooth acceleration, braking and turning. Keep helmet-bumping to a minimum. Be sure to pack the bike to keep the CG (center of gravity) as low as possible with the passenger and all that extra gear. You'll likely be riding with almost twice your normal load, so also check and adjust your bike's preload for the extra weight.
By late afternoon we rolled into Winthrop. We had aimed for no more than five hours a day in the saddle but had already exceeded that getting to town (mostly through 100-degree heat). The gals were real troopers; even though they were exhausted, we heard no complaints. Our small hotel in the heart of downtown had a total of six rooms overlooking Main Street with a cantina downstairs. After checking in we spent the afternoon exploring the town, knocking down cold drinks and sampling the local cuisine.
When we got back we tiptoed anxiously around our wives, finally getting up the nerve to ask them, "So what'd you think? Want to go again?" To our great joy (and relief) the answer was "Yes!" The planning and preparation had paid off; everyone had a great time, was safe and comfortable, and most importantly, we all wanted to do it again. Doesn't get any better than that.