pine ceiling with T&G
I did this on my attic. I used 3" 15 gauge nails. I was told to nail at the joist on the tongue of the board. I tried this, so that it would hide all the nails, but I found that it was difficult putting the next board on.
I tried another method which seemed more effective. I would get one in place, and face nailed. Then, I would add another board and tap into place. I would then add another piece. After I had two pieces on (neither nailed down) I would go back and nail so that it was easy to slide my pieces together. If you find a way that works, go with it. THere is not an exact science. I just went back and filled all the small holes, which were barely visible in the mix of all the knots and grain of the wood.