I think the best way to be a good salesman is to find the products or services that personaly you like the most and of course depending your technical skills and the second thing is to have great contacts There is not a magic way to sell.... Work hard!
I think that you just need to be unique and have good pursuading skills to get sales. Anyone can do it, just need to teach yourself and train.
Being fluent in English is a plus. Also learning everything you can about free/paid marketing methods will help greatly.
Yes your 2 original points, however market, market market...checkout my links for ways that work to get me over 60,000 visitors a month.
Sales is a skill you have to master. If your a good sales person you don't need to work hard. Sales is one of the highest paid job in the world. It's funny how it isnt taught in schools. Face to face sales or writing sales copy is not something you can just achieve by knowing the product and having contacts. It's way beyond that. Heres some examples of things you should master Story Selling Incongruent juxtaposition Power Transitions Power Words Embedded Commands Close