Here are two tips.

First - Make sure that the flight you are on is eligible for elite upgrades.
Second - (this always helps.) As a silver, if you are traveling with other passengers on the same reservation code, call up the elite line and have them separate and issue you a new one. Don't be worried, in the computers you are still on the same ticket (whether paper or e-ticket) and are cross referenced so that the check in and gate agent can see that you are all together.