The ingredients look okay, B's. I would add vanilla after adding eggs, adding each egg individually and mixing after each add.
Alternating flour mix with milk (liquid) is how I do most cake batters.
I'm by no means an expert though. And I don't bake at high altitude.
The only thing I can think of is:
1. don't open the door of oven before baking is done.
2. don't bang, slam, shake anything loudly while cake is baking.
(When we were kids and mom was baking, mom used to warn,
"don't slam anything, or the cake will fall!" And she was correct.
It did fall with loud slamming around)
Good luck. I hope wiser voices can be more exact for you.