Hello Aditi, it's great that you are learning Czech! It is a really beatiful language although a bit difficult one. I watched your video and if I were you I would definitely focus on the difference between the letter S and C. Because if I heard correctly, you have the tendency to pronounce both of them the same way (as S), the letter C however is pronounced like "ts" (e.g. very similarly to the "ts" in the word tsunami). Then the letter "ch" is not pronounced as "k" but as the spanish "j" (e.g. in the word "Juan"). Good luck with your Czech. :-)