I deal with the paranoia by focus on whatever comforting thing I have around. I usually smoke in fairly chill enviroments, so its not hard anyways. Just concentrate on the song playing, or maybe a poster in your room or something. The advantage to being stoned is you can focus super well but only on one thing. So you will just loose track of the anxious feeling, and after a minute or two you will be enjoying your high like normal again. If you aren't in a chill atmosphere, that is going to affect things. The second time I ever smoked, I got paranoid as hell, because we were lost with another weed n00b driving, we were in woods for hours it was snowing, and I KNEW I couldn't drive if I tried, so I figured he coudn't either. Until you can learn to just relax when shit like that happens, just keep your smoking confined to times and spaces that are relaxing by nature.