Help using font-lock

I'm having a problem understanding how to use font-lock-mode 
without using any major mode.

Actually, I'm editing some text in text-mode and I'd like several 
forms to be highlighted.

I tried to set the following in my init.el, but this does not seem to work

(setq font-lock-keywords
      '(("   \\*.*" . 'font-lock-string-face)
	("---+ .*" . 'font-lock-string-face)
))

I do not want to write a new major mode or anything fancy, something very simple.

I'll appreciate any help
Dan