Correct, nothing improves code quality and performance more than having the right data structures.
This is also something which I learned far too late, my programming education focused very much on algorithmic thinking. That is important, but only helpful if you have already chosen the right data structures. Many times I have had the situation that the code I was writing was confusing and only a small part of it had to do with solving the actual problem. If this ever happens to you, you should rethink your data structures and consider whether they were chosen correctly.
Also, when reading code for the first time you should be looking at the data structures before anything else.
This is also something which I learned far too late, my programming education focused very much on algorithmic thinking. That is important, but only helpful if you have already chosen the right data structures. Many times I have had the situation that the code I was writing was confusing and only a small part of it had to do with solving the actual problem. If this ever happens to you, you should rethink your data structures and consider whether they were chosen correctly.
Also, when reading code for the first time you should be looking at the data structures before anything else.