There are a couple if ways that you could accomplish this.
The first is to make certain fields required at the table level.  I probably would NOT use that option except in rare occasions.
The second, and my preferred method, is to create a "Save Button" and place the record validation code to check the fields in there.  
I believe, and Richard teaches in his courses, that you are better off having no data in a field rather than having bad data in a field.  It is up to you as a developer to decide what minimum amount of data is required to save a record.

If it is a required field, a clerk will most often put in bad data to get by the requirements.  This can cause problems down the road.  If fields are left blank you can always pull up queries or reports and assign someone to gather the rest of the missing data.

I don't know your knowledge level with Access but there are various things taught through out Richards courses. There isn't one specific course or video to point you to.
There is a section in the Access Security Seminar that discusses forcing users to enter required data.
To warn of incomplete fields start out by watching the MsgBox video.
Creating labels is covered starting in Access Advanced 4 as well as the Access Mailing Label Seminar