For me - Direct contact works best...Telephone calls and visits. The internet is good for presenting yourself, exchanging information, documents and follow-up messages...But. face to face meetings work best with me. Especially with being able to promptly answer questions - Correctly.
No matter how experienced someone is, I think it is always important to prepare (Just like you are preparing for an interview or an oral exam). Knowing completely about the product or service that you are selling is important.
And, if you are able to point out something that the client overlooked, or something that would improve the product or service for the client, that greatly helps in a sale....
I point out that most of my business involves products, or services directly related to the marketing of products - So, personal meetings, with a sample of the product, or in the client's plant or warehouse (with the product there in front of us) really allows both parties to exchange info, and even to jointly discuss some new ideas (on the spot) - Which then has you working as a team...


