And one more feature common to friendship and a rainbow: the beginning and the end of both are not certained. We never know where and when we'll find a new friend. Whatever I'm glad that you became my friend. If I made a mistake in words or phrase, please correct me. I didn't practise for a long time.
Yes, I agree with you! We may find a new friend everywhere and when we least expect it.
As for mistakes. Your speech is very good, but though you have some mistakes but not big. First of all, there's no word "certained" in English, but there's a word "certain")) and it is suitable here) and in the sentence "If I made a mistake in words or phrase, please correct me" the grammar form of the verb "to make" depends on what you wanted to say. If you meant this very message, you should have said "If I have made..." because we have the result in present and if you meant any mistake not in this particular message, you should have said just "make". And before the word "phrase" there should be the definite article. But anyway, I liked your language especially if you didn't practise for a long time! Well done!