Early and often, early and often.
For some reason, jumping into the pool and touching the bottom is not the same as going down 10 feet and staying there. I don't have to clear my ears diving down to 15' deep mooring balls, but there's no way I'm getting that deep on a normal descent without clearing every couple of feet on the way down.... don't know exactly why that is, unless the speed of the dive to the ball just happens faster than it takes the pain to register. When I first started diving I couldn't even go 6 feet down without pain , even though as a kid touching the bottom of a 13 foot pool was no big deal, but it sure gets better once you figure out what you are doing.
If you can clear at 2-3 feet of depth, as long as you clear that often as you continue downward it should actually be easier to clear as you get deeper as the percent of change in pressure as you descend at any given depth is higher the closer you are to the surface. (example: surface to 33 feet you double your pressure, to double your pressure again you'd have to go to 99 feet, not 66). Technically you should have to clear less often as you descend, however you have to make sure to do it often enough to get it done, because once you've gone just a little too far it'll be difficult or impossible to clear. If you are feeling pain... STOP, you'll only make it worse, just back off and go to the last depth you were OK at, then stop again and you should feel OK, then equalize again at that depth and then continue downward.
I get to watch people who say they "have ear troubles" all the time. Usually they're obviously skipping clearing at a spot they should have cleared. 2 feet... clear, 4 feet... clear, 9 feet... ouch... maybe they should have tried clearing at 7 feet? It's generally more of an issue of depth and speed of descent management than their ears flat out not clearing at depth.