Great guide.

First I just want to give praise and admiration to all those people out there with +10k solo kills.

One thing I would like to add, if going for max kills, skip all bosses. The reason being is the xp to kill ratio. The boss will give you more xp than a grunt solider. I know this 2 xp difference does not sound like much, but it will make you level faster, while receiving less kills.

Also, use a tablet, a computer, anything but a phone. I don't know how many times I have restarted my max kill/zero death mission due to an untimely phone call. If you don't have a tablet or a computer, make sure to use an app that will block all your calls if your service provider does not have a feature to automatically foward all calls to voice mail.