Speeds are Fast everything with Quick Start (at least if you have Entrenchment you can choose the quick start option).  Note that most of the action is on Entrenchment, which is where you'll find the 4v4 and 5v5 games.  Also, most games are Pirates Off, Locked Teams, Normal fleet size.  When you practice, try not to build more than one capital ship, at least not before you cross over 400 fleet supply and after that don't build more than 2 or 3.  In the online game human opponents will focus fire on them and take them down.  Also, try to become comfortable with each race and make sure you understand each race's strengths and weaknesses.

The online game against real human opponents is very different from playing against the AI.  Mainly, the biggest difference is that for once you'll have a real opponent.  It's like increasing the difficulty level significantly.  But don't be intimidated; everyone started out as a new player once and it is possible to learn the online game quickly and to get up to speed quickly if you want to.  You want to start out with having a very solid and thorough understanding of the game's mecahnics and the races and their tech trees.  You'll also probaly want to watch replays of games you've played in, paying attention to the good players.  Becoming a competitive online player means that you're going to take a lot of nooby lumps, but it's very much worth it.  Anyway, consider this an early welcome to the online multiplayer community.

Yep. Just ask around if there are people willing to give you bits of advice. Most people are. Welcome to SINS!

Thanks for all the advise!

Never played a game before with such a community like this...