"which dances interest me " is correct. Or we can say "what kind of dances ...?" To understand this, simply replace "dances" with another noun like "girls", "boys" or "books".

Personally I think 1. "their" refers to "techniques of disguise" and "the masks" 2. The "who"s refer to the same group of artists .

Smile and Change

Do you know what is the best gift of our life which is  that everyone has? Yeah, it’s “SMILE”, you might have already guessed it. We all like the person  people who has  have a smile on their faces. Do you like people who are always in a serious mood, scowl, and frown? Ask yourself. I am pretty sure that we never like that kind of person.

You might think that  wonder what should be the reason to keep smiling? Ponder and ask yourself again, there are always so many things we have in our life that make us smile. Then suddenly why we are filled with the scowl, frown, fuming, fretting and resentment after some incidents that might not take place in our life. We have five fingers in our hand but not of the same size, that  which indicates that time is not always the same . We see that day comes after night and vice versa. So, our life is full of ups and downs. We know it and it is the fact. If we live our life with full of tension, pensive thoughts, worry that make our life more complex. Do you know one more fact that tension blocks the flow of thoughts power, our brain can’t operate efficiently under pensive thoughts.

The best medicine in the world is “SMILE”. Keep your mind relaxed and do your work with a smile that makes us powerful, gives us happiness and joy. We always want to encounter people who have a smile on their faces and that makes us more perfect. It is said that if you don’t have a smile on their  your face, it means you are not in fully dressed,  so keep smiling. We always saw the children in our surrounding who always live happily. The main reason behind his happiness is ‘’smiling’’. They are not disturbed by any factors. They live in present moment and never worry about past and  or future. They always make others smiling smile . Learn from the children and live like they live. If we have a smile on our face then we can make others smile and gives pleasure to others. “Use your smile to change the world…don't let the world change your smile”.

You must be the change, You wish to see in the world. These are the words of the great “Mahatma Gandhi”. So smile and be the change.

Proofread and correct it, please. I appreciate you. Best regards.

Time limited,so I just corrected some "small" mistakes for you. The essay can be better organised and some sentences can be simplified. 

The sentence is wrong?as much should be so many? A technological development has rarely had as great an impact on so many aspects of ... as the growth of electronics.

A Diary

Right now I'm sitting at a meeting room listening to a boring speech.I just can't understand why there are so many trifles that I don't like but I have to do and I have to let them waste my lifetime .Why there are always lots of people who just want me to grow in the way they like.There are so many delightful things in lifetime,and as I see,the most interesting part in life should be that I can choose what I like,then try or feel it .
Maybe when I graduate from university, I can become more independent,there won't be Formalist things in my life.

The diary is OK,but just a bit Chinglish. Hope you can do better.