1) Choose your spot carefully, I would suggest out in the open so that your loved ones will not have an onerous clean up job
2) Select your weapon with care for the same reason, use a small caliber to prevent widespread blood and brain spatter.
3) Also if you score a through and through you will not endanger your neighbors
4) I realize that you are making a statement to protect your rights to semi and full automatic weapons, but select single shot please to avoid accidental overspray as you fall on the gun
5) Please advise the proper authorities via time delayed email where they can pry your weapon of choice from your cold dead hands. It will make it easier for them to comply with the law and remove one more gun from society
6) If your intentions are clear, and you have no doubts about the rightfulness of your action, do not clutter up the suicide hotlines. They have enough to do right now.
7) Make sure all your paperwork is in order, place your gun permit on top of your last will and testament and other useful documents that your loved ones will need.
8) If you feel compelled to write a suicide note, contact your local NRA rep for fill in the blank templates. They have proven themselves to be quite good at this.
9) Try to reject any ideas that anyone will care for your reasons, just accept the fact that you have the right to bear arms, the Second Amendment allows it.
10) Finally, in the spirit of defending that right, don't ask anyone else to pull the trigger that blows you away by challenging local law enforcement people, they have enough to do protecting our children from people likeyou.