Communication skills would be my number 1
The thing most lacking in my experience is documentation. The ability to write accurately and coherently, to understand spelling and grammar, together with the ability to explain things to those less technical or less experienced is what is most needed among IT people - and also people in general. To single out IT as needing particular skills is good but it should be mentioned that IT is not the only profession which is lacking in some of these skills. The majority of journalists, in my opinion, could do with taking a course in the correct use of English with particular emphasis on grammar and spelling. After that last remark, I had to go back and ensure that I had made no spolling mistooks!
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