I would say pick a weapon, A2G or A2A, and practice with it until you know the basic characteristics and what it's going to do in the DCS Sim. Once you're comfortable move on to the next weapons system.
It's easy to get behind trying to master everything so keep it simple. As already said, look at Chuck's guide and watch what others are doing/saying.
This isn't a race.
Just my 2 cents