Tabs are okay, but dangerous. If end up doing any revision or working on your resume in different computer labs, your tabs are likely to wander on the page leaving ugly blank spaces in the middle of your text. An alternative to using tabs or indenting with the ruler is to use a table to create columns and rows. Tables have the advantage of translating nicely into html pages. If you use a table, use one row for each topic.
Bullets are more effective than dashes or asterisks in lists.
If your resume runs more than one page, always set up a header with at least your name and the page number. Learn how to use paragraph borders and horizontal rules. A well placed line can be an attractive and effective element in a resume.