To get a student visa in USA, is it necessary to consult any angency? Please help me
What should I do to progress my proffessional career in USA?
You don't automatically need to consult (and pay) an agency.
The official US government website tells you exactly what to do:
https://educationusa.state.gov/your-5-steps-us-study/research-your-options
If you are trying to get a student visa, I assume you are planning to be a student. Your school should have an office that will give you all the information you need to obtain a visa. I would suggest avoiding an agency because they always charge you more than just going through proper government offices would charge. It is a waste of your money. Just check with the school and with the web site leics2 above gave you
"What should I do to progress my proffessional career in USA?"
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Double check the spelling for all documents you fill out is one thing you can do! 
From the username I suspect the poster was trying to set up for spam. My intial reply probably stymied that! 
[quote]From the username I suspect the poster was trying to set up for spam. My initial reply probably stymied that! /quote]
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Yep!