Skype Call

Your English is quite good.  I would like to comment on it for two reasons.  I'd like to provide suggestions for improvements.  I would also like to encourage you!!!

You wrote:
>>I have joined two times of the Skype call
I suggest:
I have twice joined the Skype call . . .

>>on the internet which was bade by Sedgehead.
on the internet hosted by . . . .

>>His voice is so attractive and the pronunciation is so standard
Thanks for your compliments.  I've lived in several parts of the US so my voice blends different regions and suits the standard for the US.  I surely have a strong American accent, when compared to an English or Australian accent, for example.  So, it is not perfect because there is no "perfect" in any language.
>>(May be you could say your Chinese pronunciation is standard too) but I like it so much.
Perhaps.  I only learn Chinese the hard way, but I by listening.  I'm only imitating what I hear!

>>Because there are several friends stayed in different city as well as the English level.
". . . friends from different cities as well as people with different levels of English skills . . ."
This sentence is what we call "a dependent clause."  As such, it is not a completely sentence.  I would ask "Because . . . what?"  The "what" part is missing.

>>I must adjust my attitude to study here just wanna gaining a little knowledge to keep pace with them.
The pace will always vary.  I try to slow down when I know someone needs me to go slowly.  If the group seems to understand me well, I'll speak more quickly.
>>Two times past, I found myself was unimproved, Because I daren’t to speak out but listening yet.
These two past times, I found I lacked improvement because I dared not to speak up but only listened.
>>This will be considered lost of confidence.
This could be considered a loss of confidence.
By the way, I like to say "those who never speak, never learn."  That is, while it is fine to listen and learn, we learn faster by speaking and trying even if we say many things wrong.  You will find I may often say things incorrectly in Chinese.  But I'm learning when I do it!

>>I have got some preparation on the second time lesson, but finally I couldn’t understand it partly.
I suggest: "I was partly prepared for the second time lesson, but finally I could only partly understand it.

>>So I decided to read Sedgehead’s article till I understand it completely.
The word "decided" is past tense.  That is correct.  You should continue to use past tense by using "understood."

>>For each lesson I will be more industrious than the others from the beginning on the following lessons.
I'd suggest you not compare yourself too much with others.  Only strive to improve yourself.  Some others may have much more practice than you.  Or perhaps they can pay better teachers or someone paid for them to study English.  I only compare myself with me.  Am I improving day by day?  That's all I worry about.  

>>Hang in there!!!  My dream will come true!!
Exactly!

I'll give you another example.  Some Americans hear Spanish or Chinese spoken frequently.  Maybe they hear people speak other languages such as Tagalog or Farsi.  I don't worry about others.  I just worry about me.  The fact I know no Chinese speaking people in my home town does not bother me.  With the internet, I can still become fluent.  All I need is to hang in there and be persistent!  I will follow your advice!  pH