ALL English sentences begin with capital letters. There are NO exceptions to this rule, even when writing online.
Secondly, the pronoun "I" is ALWAYS capitalized.
In English, the names of people, the names of most places and the names of some things are to be capitalized. "The deserts of Saudi Arabia have miles and miles of sand dunes." "My father lived for a year in the Gobi Desert."
"Did Andrea take the books to the local library?" "No, she took them to the Midtown Law Library."
"This website provides assistance for Arabic speakers who wish to improve their English."
Your very first sentence is an interrogative, therefore, its proper punctuation should be a question mark.
You should be careful how, when, where and why you use abbreviations. If you want to be cool, hip, with it, in the 'in-crowd'; go ahead and use them like you've done here. However, if you want to be taked seriously as a writer, use them much more sparingly.
Your use of punctuation within, between and and after sentences could use some work. Here are some simple rules:
At the end of sentences, there are to be two spaces following the final punctuation mark, preceding the next sentence. (NOTE: some websites, such as this one, default to a single space after a period, so you will not be able to override this when typing online.)
The most abused punctuation in English is the comma; either for overuse, misuse, or lack of use. You have managed to commit all three of these errors in your post.
Try this instead:
Hello, how are you? I would like some help concerning translation because I'm studying English/Arabic & Arabic /English translation. I don't find enough material, which is why I'm looking for effective websites; whether about theoritical translation or practical translation, and any tips on how to improve my translation in general would be very much welcomed.
Thank you in advance.