Learn to calculate quickly but most people slow down to speed up and you dont want to do that. When developing skills the trick is to spend time developing the correct techniques first then speed it up, the speed comes as the brain automates it. Whether its athletes developing motor skills or chess players developing visual and thinking skills, start slow, get it right, then speed it up.
Blunder Master Here.. How do I stop making so much blunders?

This is all great advice. There may be a reason that so many people are saying the same thing. If your friends don't want to play longer, you can always play other people. Good luck with your goals.

Ooh, I'm gonna hang around to see if the OP reads llama's link. (No indication yet that he's going to, but ya never know...)

A compromise might be to mix in some games against bots, which would allow you to take time to think about your moves while not having to wait for your opponent's moves. I know there are plenty of negatives about playing bots, but those objections shouldn't really apply if your main goal is to catch your own blunders.

As a beginner I try to oppose my tendency to take every piece, but to build defenses. This helped me reduce blunders. I play 30 minutes games.

Look, I am not changing time controls. They are too long. So saying that I should play long is not really helping. Besides my friends won't play 30 min.
Besides I tried 10 min and it was not too long or too short. Just right.

Look, I am not changing time controls. They are too long. So saying that I should play long is not really helping. Besides my friends won't play 30 min.
Besides I tried 10 min and it was not too long or too short. Just right.
You're the expert. I guess we should be taking advice from you...

When you play chess, play chess; don't listen at the same time to music or watch TV.
Later on, when you stop blundering you can expand your awareness....

Look, I am not changing time controls. They are too long. So saying that I should play long is not really helping. Besides my friends won't play 30 min.
Besides I tried 10 min and it was not too long or too short. Just right.
You're the expert. I guess we should be taking advice from you...
Yeah, it is weird. Rated very low and asks for help, then tells people their advice is bad.
In his defense, his profile says he's a little older than 8.

Look, I am not changing time controls. They are too long. So saying that I should play long is not really helping. Besides my friends won't play 30 min.
Besides I tried 10 min and it was not too long or too short. Just right.
You're the expert. I guess we should be taking advice from you...
Yeah, it is weird. Rated very low and asks for help, then tells people their advice is bad.
In his defense, his profile says he's a little older than 8.
OK, I guess that explains it, haha.
Now I know that you probably say that I should play 15 minutes to 45 minute but that takes too much time and I have to manage my club and also watch some of the chess lessons.
Well, you seem to know the answer, at least part of it (but you do not seem to like it). The thing is that there's no silver bullet, no magic formula. You should play longer games, do a lot of tactics exercises/puzzles and analyze your games. And slowly, bit by bit, you'll improve. If you don't, you'll continue to make blunders. As simple as that.
So there must be some other way to decrease blunders.
I gave you a link, you should read it.
But also, in chess and every skill in life no matter what it is, the only way to be fast and accurate is to first be slow and accurate.