This is something I kinda made up, but I'm not the first to come up with something like this. I have thought a bit about this and I think I have come up with a pretty good and solid map to the otaku attitudes starting from the Barely-Otaku Mellow Admirers to the die-hard unhealthily obsessed weaboos. I'm sure one of these descriptions will fit you or someone you know. Enjoy.
Level 1 - The Come-Acrosser
This can hardly be considered an otaku, but it exists nonetheless. The Come-Acrosser are people who suddenly found one episode of one anime on televsion, usually Cartoon Network or Adult Swim. They take interest in this show because of the story line or a specific fight scene or character and begin to watch it, but really can't watch any other anime. Usually the anime they "come across" is Naruto, Dragon Ball Z, Pokemon, or Inu Yasha. Eventually, the Come-Acrosser gets tired of sticking around for so many episodes and they realize the show will keep going on and on and on and they finally get bored of it and stop watching it.
Level 2 - The Mellow Admirer
This is usually the stage every otaku goes through but only sticks with it for a few months before moving onto the next level. Some people never leave this stage. The Mellow Admirer likes anime and watches whatever they can find on television, Comcast OnDemand, or YouTube. They enjoy dubs and can't stand it when they find a subbed anime. Mellow Admirer's usually like the anime that every otaku has known, but to them, it's as if they just discovered it and it's the most awesome thing in the world! Their behavior is actually seems silly to the much older and more experienced otaku. Mellow Admirer's also can't stand higher levels of otakuness because they feel that "they like anime, but they don't believe they can ever act like THAT". Mellow Admirers should never be invited to a convention. They usually won't appreciate going to one. Usually it is the Mellow Admirer who discovers hentai. Lucky them!
Level 3 - The Fanboy
This is usually when an otaku can start being called a "Weaboo". The Fanboy expresses interests in going to conventions and might go to one or two and enjoy the panels, usually cosplaying as a Death Note character. They also start liking subs but still prefer dubs over subs. About 30% of their money goes to anime-related things like posters and plushies. They also might start buying manga from their favorite anime. They also are starting to get into better anime, but the kind that you don't usually know about from just watching television. You may find Fanboys searching anime websites and forums for some great anime. Their speech may also be speckled with words like "Kawaii" and "Baka" as well as a lot of things they talk about have to do with anime or the manga they read.
Level 4 - The Actual Weaboo
This is when an otaku because extremely annoying to non-otaku folk and some people may even not enjoy their company at all. The Actual Weaboos now watch anime that have no dubs at all and actually they become increasingly annoyed with dubbed anime and claim that there "isn't enough emotion" in Ameircan anime. The well-known anime like Naruto and Pokemon become their least favorites and reffers to those types of anime only as "my starter animes". Conventions are a yearly thing for them and they usually spend months trying to save up money for them just so they can splurge in the mountains of merchandise. Usually 40% of their money goes to anime related things. They also start buying cosplay costumes on the internet or in stores and sport them at conventions. Usually, they dress as Kingdom Hearts, Final Fantasy, or some well-known anime character. Their speech has also gone from only a few Japanese words to entire phrases they ripped from an anime, and also pronounced and said just like the character who delivered the line.
Level 5 - The Otaku
This is the level every Actual Weaboo reaches. Their room is covered with plushies, posters, and Japanese toys. The anime The Otakus watch are usually anime that no one knows about, except those who have already reached this level too. Otakus not only attend conventions multiple times a year, but they usually run panels at the conventions or volunteer with a show at one. About 60% of their earnings go to anime merchandise. Otaku usually never buy manga unless it's on sale or brand new and usually reads anime on the internet. If they didn't do this, almost all their money would go to manga, with the amount that they read. Usually Otakus become interested in visual novels and other Japanese video games. Though Actual Weaboos and Otakus can be very similar, the major difference between the two is that Otaku have a deeper appreciation for Japan as a whole, not just the anime and manga. They may try to go to more Japanese restaurants or cook Japanese dishes. Japanese culture absolutely fascinates them and they yearn to go to Japan one day. Some even try to save up or enter contests to win trips. Otakus are usually looked up to from other levels as the big sister. If someone from a lower level wants to ask about a certain anime, usually the Otaku will know something about it. Otaku isn't something to be ashamed of and usually takes years to get to.