Take a version control approach. It doesn't have to be too complicated, but you should keep a history of structure changes in a table. Some developers use a text file (.sql) or hardcode it in code, that's fine, just don't make changes in the interface (i.e.. Access or Enterprise Manager). Changes should be made programmatically, or in a method that they can be played back.
An assumption to this is you have a front-end and backend table that is used to record the version number.
Figure: Never make a change manually in Enterprise Manager or Access 
Figure: Always save your changes in script 
Figure: Name them in the order they're executed 
Figure: An example of a backend table recording the version numbers
Tip: If you’re using Next Gen and you’re changing just one table, then just regenerate for that table
| We have a program called SSW SQL Deploy to solve this problem and automatically make schema changes. |