Lots of excellent replies on the subject, but I might have a suggestion that will make it more comfortable to "get your feet in the water" initially. If you lean gradually while at a relatively high cruise power setting you are going to spend significant time in the "bad place" before you get LOP. I practiced a little with the "big pull" - not turning the mixture knob, but just pulling. Start at a runup power setting where you can't hurt anything and pull until the power drops off noticeably. If you listen carefully, the engine noise changes to a "smoother" or more "mellow" sound at the same time the power drops. That's what you
are looking for. Now in the air do the same thing. Pretty soon you will be able to lean just by the sound and feel and get pretty close to the setting you want, hopefully without the passengers becoming alert :-). You can fine tune from there.
Just what I did. YMMV
Gary Casey