As stated, you missed it for this year. Mark your calender for about March of next year. Applications for tags and preference points is open from about then to about April 1st. You have to apply just like you are applying for a tag, but just mark "preference point" on the application.
The good news is that they only cost $25 per species. However, the bad news is that you will have to send them the full amount of the cheapest tag of that species for them to hold for several months, then they refund all but $25.
For example, to apply for an elk preference point, you have to send them $355.25 I believe. After the drawing (usually mid June) you will receive a refund check for all but the $25