You cannot be completely anonymous. If you want to be anonymous for everyone on the internet, follow these steps.
/* I forgot to add this. Use a different user on your computer so you're not using your same keys and personally written software. If somebody gets a payload on your computer they can find all your personal files that will probably have your name and if that fails they could get the names of wifi networks in your area and get your location. */
1) Buy prepaid cards (non reloadable) for everything.
2) Buy a cheap burner phone. Make sure it is Android so you can use apps without needing to keep paying for plans.
3) Create a PayPal and maybe a Facebook account under your identity. Some places that don't take prepaid cards allow PayPal.
4) Sign up for a VPN service. If you use your own VPS, you will not be anonymous from your new identity. This can make it easier to find your real identity. A heavily used VPN service with many locations is best. If you start outting transphobes under a VPN IP that you use all the time, anyone trying to dox you will know to look for die hard LGBT activists.
5) Never associate with any previous accounts, users, or web sites that you have had contact with.
6) Don't display any strong interests that you have or have shown under other identities.
7) Never use your real information on any account. Even if your accounts get hacked or the provider is social engineered, you will not be found.
Use a VOIP number wherever possible. It will save you money and reduce the chance that somebody can maliciously track your prepaid phone.
Not sure about this, but somebody might be able to find you by filing a lawsuit. If you use a phone the cops could track its location