Wait, I can probably play this game now!
Anybody got recommendations/advice/whatever for a rookie?
Try to find a Merc Unit to join - those are Groups of Players with own Teamspeak Server.
There are many recruitment threads in the official MWO forums.
MWO is much more fun if you can play with friends and teamspeak.
The alternative to Teamspeak is the C3 Voice Chat. The group function of MWO that allows you to play with friends in a group supports this application, but you have to download it separately.
Play fast Mechs first, but stay next to other, bigger Mechs.
Acting as Backup, and fight other light Mechs that try to hit and run.
If you get enough C-Bills, buy a Jenner or Raven.
Buying a XL Engine is also a good Idea, because you can remove the Engine and use them in an other Mech.
But be aware that a XL Engine is also destroyed if a Side Torso is destroyed, so use it only for fast Mechs.
All Mechs are limited by the weight they have for weapons.
You can get more free space by upgrading:
A XL-Engine gives you the most free space, but makes the Mech more vulnerable
Double Heat sinks are expensive, but can save a lot of space otherwise used for additional Heat Sinks
Endo Steel give you between 1 to 5 additional tons
Ferror Fibrous is a waste of critical Slots, and only to consider if your Mech has a lot of free slots after upgrading to Endo Steel, Double Heat Sink and XL-Engine.
Always target your enemy with R, and aim for weak spots.
If the enemy Mech isn't damage, aim for the Arms, because that's the Zone with the thinnest armour.