Getting ready (for long rides and touring tourists)
Make sure your bike is in good shape. Good brake cables and brake pads, non-worn chain, blades and sprocket set, good tyres, derailleur, axles and paddles. Biking tour guides may help with repairs, but some cannot tell the front from the rear. Better hope that one of your companions knows his shit.
Make sure you are also in good shape. If not, you may end up hitchhiking or riding the luggage bus all the time.
Take along the most common spares, repair materials and tools. Some companies may have only tools to fix the luggage bus.
Don't try out your new clip-on paddles in Bhutan. One such idiot managed not to get his shoe from his paddle in time and ended up hanging over the edge of a cliff. Lucky bastard.