From here, you have three choices; you can do all, none or some of the following:
1) Join a team as a sub. Put up a recruitment thread[pastebin.com]
on the ETF2L or UGC forums or r/tf2lft, saying you have prior experience of TF2 in pubs and are willing to learn how to play competitively. Make sure you mention where you live, any relevant experience, what times you can/would like to play, and what you aim to get out of it. You will need a microphone and many teams like to use Mumble[mumble.sourceforge.net]
(which is a free download), and you may have to do a number of trials to find a team who want you (Depending on how in need of a player they are), but your communication, gamesense and general skill will increase dramatically, quickly. One downside of only playing PCWs with your team is you will have a limited amount of time at certain times of the day, which may not suit certain people.
2) Join a Newbiemix and play with others in a similar position to you (North American is here
, European 6v6 is here
). You will be given a mentor and a set of fresh new teammates; the mentor will teach you the basics of the game, your classes role, and other important things such as what to call to your teammates. The benefits of this involve more communication, more flexible hours and a friendlier atmosphere than lobbying; however, be aware that there may not always be demand for your skill, and you will not have the luxury of choosing people you want to play with; they will contact you, not the other way around.
3) Play a few TF2lobbies[tf2lobby.com]
. This is how i personally started on my way to competitive – a few 9v9′s, then 6v6′s; although understand that in many ways it is different to playing in a team, especially in the communication side, which means that many people (myself included) advise strongly against it being your first experience. Lobbies act as a way to play with and against people of a higher skill level than pub servers, and act as a form of anonymous mix service; they’re very good for learning the absolute basics of competitive, such as rollouts, minor callouts, and working on DM (Stands for Deathmatch, or ‘how well you kill the other guy’). On top of that, they’re available 24/7, and you can start immediately. However, watch out for people with inflated egos, who believe that because they have done x lobbies they are the best in their classes field; this is nonsense, as there is absolutely no correlation between lobbies played and ability to work as a team. If anything, these people tend to lone wolf a lot and sacrifice others in the team for their own personal gain. On top of that, they will have severely underdeveloped communicative skills compared to a team player. In all, it’s very easy to get into, and with the offering of Highlander -and- 6v6, worthwhile to play against a higher standard of skill than pubs.
As of late 2013/14, you can now join lobbies at TF2Centter[tf2center.com]
, which is currently in beta - they generally fufill the same functions as tf2lobby, but they may also ask you to use a headset ingame.