Players at 1200 stop blundering pieces and play mostly decent openings, and solid structures. 1200 is around 60-65 percentile, so above average player.
1400 is 80% percentile. 1800-1900 is 98-99% percentile. 2000+ is top 1% of players on the world.
You have to get through a lot of good players at every juncture.. so there are thousands of people in the 1000-1200 range, including people who have formal training etc.
Just keep playing more games and making better moves and you will break through. Tactics trainer helped me a lot too. I'm approx 1400 now, but I feel close to 1500, because I get stuck at a rating for a while and hit a wall, and then I break through and surge. It can be really frustrating when you feel like you're playing below your talent level. Memorizing openings and end games is a short cut to success, but I don't do that. I like to learn naturally
You are an 1100 in blitz. The 1200 rating is probably the least likely to be accurate of anybody you play since most players user it for their initial rating. It makes sense that some 1200's seem to play like grandmasters to you. They may be 1600's who just joined. Others play like complete patzers. They may really be 800's who just started.