There are about as many approaches to macro photography as there are macro photographers. So don't be shy about trying different approaches, like AF (it has its uses), handheld, tripod, ambient light only, 100% lit by flash, reflectors, diffusers, focus stacking, 'absurdly' high apertures, etc, etc. You should fill your macro toolbox with as many techniques as you can, and use whatever makes a given photo work for you.
Regarding a macro rail, I picked up one of these last year:
Oben MFR4-5 Macro Focusing Rail MFR4-5 B&H Photo Video It appears to be the similar to a popular Velbon model, but with a handy quick release plate. For the price, I'm happy with it.
Also- have fun! With your new macro setup and your new garden