Most Job Hired by Merit or Presentation Skills?

This question is best answered by considering what is “value”. In the form of electors, the person proves that he can do well, and if they live, can be no doubt deserve it. Add to that the fact that it is successful as a person reasonably well at work and in fact can not determine if the person is not elected to do something else. Show the light of the most successful people know and often wonder how dozens of other equally qualified to do minor works. It is likely that the successful people we see at the top you got there first, with a projection of themselves, and then the best options that you created. Moreover, many qualified people rot in smaller roles, because they are skilled in design for the right job or job changes.

Or shall also use to improve their knowledge?

Probably the world would be better if the responsible person shall submit its compliance and tone in their abilities to find a job so they could compete and be selected for positions that they deserve.