I'm not in a good place to make a movie but I did make a note of every step solving a not-too-easy one, so let's see if this helps? And let us know.
Also, I'm no expert and would love to hear of any shortcuts. I haven't failed to solve one in awhile now but am usually quite slow. Advice from y'all who are fast would be great!
Anyway for you asking for tutorials: Print the grid, clues and narration... find a quiet place... have fun -- and keep at it!
1. Clue #1 tells us Switzerland is not 1999, Nyalt is not 250 feet. Often that's all you can get initially from a clue of this type.
2. From #2 we know 1999 is not the tallest, Nigeria is not the shortest, 1999 is not Nigeria. Don't miss that last part!
3. #3 is interesting. The logical way to read it would (perhaps) be 1994 is not Nigeria or Ogiano and that's it. However, there's a rule with these puzzles: also we can exclude Nigeria and Ogiano. After Puzzle Baron told me this I now read the clue differently. Nigeria is not Oginao, Nigeria is not 1994, Oginao is not 1994… and we are done with #3 so check it off.
4. Clue #4 only tells us (now) that 1996 is not the tallest, 1994 is not the shortest.
5. Here's that clue type again! Oginao is not in Canada, 245 feet is not 1999.
6. #6 is self evident, exclude the combination and check it off as done.
7. #7 is also self evident.
8. #8 says Roqua not tallest, Oginao not shortest.
9. #9 is self evident.
10. #10 is self evident (and a truth, finally!) and we're through the list once.
11. Back to #1, 1999 is not 250 feet tall so Nyalt must be 1999. Switzerland is 250 feet, and is also 2002.
12. Copy the exclusions on the 250 foot line: Rhoqua and Sihat cannot be 2002, Nyalt Rhoqua and Sihat cannot be Switzerland.
13. #2, nothing right now. #4, 1996 cannot be 245 feet.
14. #5, Oginao cannot be 1999 so is 245 feet. Garray must be 250 feet, 2002, Switzerland. Canada is 1999, and is not 245 ft.
15. Oginao at 245 feet is either 1984 or 1996, and 245 feet can't be 1996, so Oginao is 1984 -- and can only be Jamacia.
16. When we fill in 1984 and Jamacia we see 1996 must be Nigeria, and 1994 Brazil.
17. Observe #5 is done, #8 is done.
18. From #2, 1999 can't be 240 ft.
19. Here's a common pattern: from #4 we know either 1994 or 1996 must be 235 feet, so this excludes 1999 at 235 feet. Bingo, 1999 must be 230 feet.
20. Match feet and years with years and countries: Canada is 230 feet, Nigeria is 235 feet, Brazil is 240 feet.
21. #2 and #4 are done and in fact now we have only the grid. This is a good thing! Provided there are no mistakes in decoding the clues into X's and O's (and I make mistakes all the time, no worries clear and try again, and get better all the time)... when the clues are done and the grid is accurate, we start applying our hard logic and great experience with these puzzles (ha, my point is we no longer need squishy vague per-puzzle clues, but instead universal rules of logic puzzle solving, if you see my point).
22. Look at the top row: 230 feet is Canada and 1999, and 1999 is Nyalt, so Nyalt is 230 feet. Rhoqua is 240, Sihat is 235 and we're done!
The right answer in 22 steps and no math! Perhaps not efficient but still... perhaps it'll help somebody?