It is quite common that your rating fluctuates 100-200. Especially if it is your first dozens games, as a single victory can enhance your rating by 50-100 points.
Do daily tactics trainer, analyze your games, read chess books. Proper self study is often enough, especially at lower levels. Keep in mind that the odds of finding a 'stranger' who will help you for free will be very slim.
Well, last month my rating in blitz chess is around 1500. But next month later my rating was dropped to 1390-1400.
I want some chess mentors to play and train for me. Recommend some tactics or indicating my mistake in each game.
Thank you!