If the NSA wants to know where u are u are pretty much fucked and should find refuge in an embassy,
...
(or maybe for the FBI).
^this basically. If you've already made enough noise as to have attracted the feds, or worse, the NSA, then its too late for anonymity. If thats the case, even completely avoiding all electronic communications might not be enough to evade their watch.
In your question you specified as anonymous as possible, so I'm going to try and think of, and apply as many levels of anonymity as I can think of.
I would definitely start with booting a live distro, TAILS being the most efficient (most likely) as it has been designed from the ground up for privacy and anonymity. Next you'll need to configure how you will connect to the outside world. In this case since we're paranoid, so hop in the car and drive a few hours to a large metropolitan city (if you already live in one, then you might have to drive farther to find another.) Once youve found a suitable city, purchase a prepaid creditcard with *cash.* Before heading back home, find an open wifi network, or better yet hack an encrypted network (WEP is easy, WPA(2) with WPS would be a better choice.) Once your connected to the internet (while booted into TAILS) rent a server, use fake name, address etc and pay with your prepaid creditcard. Make sure your server is located offshore, in a privacy friendly country like iceland, denmark, france or switzerland. Configure a VPN server and TOR on your new box. Now you can go home.
Now you'll need to purchase a prepaid burner simcard and mobile hotspot, probably would have been a better idea to purchase that before you came home... thats not your fault though, your new to this so I'll let you off on that one. Immediately once connected to your new hotspot, connect to your vpn and then out from your vpn through tor, to the internet.
Once on the web,
NEVER use your real name for anything
NEVER tell personal stories or the like.. no matter how arbitrary and generic you think they are.
ALWAYS spread disinformation, make a back story for your alter ego and stick with it.
NEVER order anything to your home address
NEVER communicate to personal friends or family while using your anonymous connection
ALWAYS disable javascript
NEVER install flash, or JAVA browser plugins
and lastly (because im getting tired)
ALWAYS use tor browser (as opposed to a common browser set to use tor as a proxy) this is because tor browser emits the same fingerprint no matter what device its installed on so every tor user using a vanilla copy of tor will all give the same fingerprint. browser fingerprinting has shown to be pretty accurate and it seems the more you do to try and avoid this the more unique your fingerprint becomes in most cases (i could go into detail but browser fingerprinting is beyond the scope of this rant, but i suggest anyone that isnt familiar to read about it.)
Any way you could basically keep adding inifite layerrs of anonymity but the more you do, the more limitations you will encounter and the less enjoyable your web experience becomes. So what I suggest for anyone is to first determine exactly how much privacy and anonimity you require and go from there, and also don't forget that being so quiet on the web can attract attention on its own, so disinformation and alter ego's are a must. Don't be TOO quiet.