Keep it brief.
In general limit them to only 3 or 4 of your most important points.
Remember your goal.
All of your talking points should build to and support the goal of the meeting, whether it is simply educating the legislator or asking for support. If a talking point doesn't help with that goal, get rid of it.
Personalize your points.
Convey local and personal stories that illustrate your message and the impact of the issue. If possible reference areas or locals within the legislator's region.