Google and alt-tags

I think I remember seeing a discussion on AO on alt-tags and the way they are supposed to be used a while ago. If I remember correctly, the "official" way for them to be used is as "back-up" for pictures that don't load. The discussion also mentioned something about how Google treats them, and I just found out first-hand that it's not a good idea to cheat with them.

Here's what I did:

picture1 with alt-tag "keywords 001"
picture2 with alt-tag "same keywords 002"
picture3 with alt-tag "same keywords 003"
and so on...

Before I did this, I was ranked #7 for those keywords on Google. I wanted a higher ranking on some other search engines, so I applied that "trick".
Result: Google mercilessly kicked me out... heh: I'm nowhere to be found on Google anymore.

Lesson learned, I guess :)

Anyone have any tips on SEO that actually work?

Ouch! bloody google, messing with the common folks again. Used to be there was a day when good old hard american currency would get you that coveted number 1 spot on google's searchlist... Now they kick you out for doing the old metatag routine within alt tags... that just sucks. You have my sympathy.