I never had a good method of counting crotchet triplets, they always gave me trouble.
Here is a very good video on the subject.

A bit late, and I haven't watched the video but here's the way I get people to do it, this example assumes that we're in 4/4 time.

It's not easy to count three against two, and that's what makes triplet crotches initially awkward. It's much easier to count three against one, which is why triplet quavers are easier. So here's what we do.

1) Count the crotchet beats - 1,2,3,4 etc
2) Now count the minim beats, two to the bar, coinciding with crotchet beats 1 and 3 that you were just counting - 1 - , 2 - etc
3) Divide each of the minim beats into three even counts, 1 and a, 2 and a .
4) Lose the words '1, triplet' etc, replacing them with something that runs off the tongue much easier. The word 'Andover' is perfect for this. You can't easily say Aaaan Do Ver, or An Do-o-o-h Ver, or An Do Verrrrr. The word has three even syllables, so whilst tapping your foot to the minim beat, say "Andover, andover, andover" etc and you have the perfect timing for your triplet crotchets.
5) Of course if you start the word on the second syllable, you get "Over and over and over and....." which is also very easy to remember.

Andy. A very good explanation! Haven't heard that one before. Hugh