yeah, golden rules 😉
1. Select only the data you really need. So select the needed columns and create a where close who gives you only the relevant data.
2. If working on huge data, indexes can be usefull. Too complicated indexes will kill your performance.
3. Use the right formats on datasets. $200. isn't usefull to store yes or no. Same idea on numbers, don't store them as text 😉
4. data is stored on other disk than your sas work.
5. go on...