I'm absolutely useless with rods or the Y stick, but ok with an improvised pendulum.
With that I can get direction markers as well as direct answers, so changing position you can triangulate to find what it is you are looking for.
I used to practice but I haven't done so for a while.
When I had a farm property I needed to find the water stop tap, to change the plumbing, but it wasn't marked on the deeds, and the neighbours didn't know either. Dowsing was about the only choice after a good look around drew a blank.
Neighbour thought it was funny at first. But after a few walks around I settled on a spot that I got a good indication from, then marked it and fetched my spade. I was intending to dig a trench 3 ft deep for as long as it took to find the pipe - then more digging to hopefully find the stop tap.
I put my spade in, sank it in with my foot - and hit something hard about 8" deep. I uncovered what it was expecting it to be a boulder, but was surprised to find it was the cast iron housing that the stop tap was under!
So - a 30ft x 15 foot area that it was likely to be in - and I hit it first time.
It was only 5 inch square.
I used it again when my wife lost an earring while mowing the grass....4 acres of grass ! With a pendulum I walked the area, and got various bits of information. One that it was hidden under cut grass, and another that it was damaged. Then I triangulated to a spot near the fence, and moved a few clumps of grass with my feet only about 2 feet wide -and there it was. It was also damaged I think when the mower blade hit it. So, right on all counts.
After a while using the pendulum I was getting replies to questions in my head before the pendulum was indicating - which happens with some spirit communication too - often before I have finished asking the question out loud.
I have now taken to using my right hand -slightly cupped to feel for things to find them. It works just as well if you focus on what you are looking for - this is important in divination. Some water diviners use a colour wheel or similar correspondences to link with what they are looking for.
This usually works very well for me. The only downside is time when you are looking for objects. As in if an object has been in a location in the past I get a response, so I get false positives if something was in a location but has been moved. Works much better on items that have been in a location a long time or are new to a location. Not so well on car keys that have been in multiple places recently in the same room.
How it works? I think along the lines of sympathetic magic where you are feeling for a similarity between what you are visualising and the item. All things seem to have a natural energy about them, a vibration, so I think it is just your body picking up on that.
Anyone wanting to practice I suggest getting 6 empty matchboxes, and putting some salt in one. then mix them up and try divination to find the one containing salt. At least that is how I started.