So beyond the standard play with your team and so on I figured there are some things that can help a new player.
Feel free to comment and add to the list of things a new guy might want to know.
1: How to change your Loadout
You recieve Loadout cards from crates. At the start of a game before you spawn in, simply click on your merc portraits at the top, then click the merc you want in that slot and you will be able to pick a loadout card.
There is a great wikipage on loadouts here http://dirtybomb.gamepedia.com/Cards#Weapons
2: Escorting objectives
When a map requires you to escort a vehicle it is required that atleast one person from the escorting team is close to the vehicle for it to move. If the vehicle is not moving it is easily disabled by airstrikes.
3: Fraggers Grenades can be cooked!
By holding the skill button on fragger you can cook his grenades. The timer is indicated by him lifting his fingers counting to three. If the grenade is not released it will explode in your hand and kill you.