Since there are a lot of more veteran decks out there it may be difficult at first. Once you reach level 3, I would suggest milling a couple of decks you don't intend to use - i.e. If you want to focus on monsters and skellige, mill all your cards in scoia'tael and NR. This will allow you to craft a few more decent cards in your card collection to use for the decks you do intend to play.
Also, go check out the deck strategies in tacticians corner. There are some helpful pointers over in that sub-forum. Focus on a strategy. IMO the easiest places to start for the various decks are.
Monsters - weather deck
Skellige - resurrection & graveyard deck
NR - medic/promote/trebuchet deck
Scoia'tael - wounding / special card disruption deck w/ Hawker support
None of these decks require too much more than your basic deck to get started and all can be built up into very successful power decks eventually.
EDIT:
JeshE moved topic to tacticians corner sub-forum.