If you want to learn how to be good at B2B marketing you need to understand that you always market to people first. People sign checks and place orders, not businesses.
That said, I would highly recommend you read all books and ebooks by Seth Godin and subscribe to his blog:
Now, the key to B2B marketing is trust. Decision makers must trust you and your business to buy your products and services, without trust no one will buy anything from you. For this, I recommend Trust Agents by Chris Brogan and Julien Smith.
On the subject of persuasion, to learn how to be persuasive in marketing and every day life, I highly recommend Fascinate by Sally Hogshead, it gets into details backed by research into 7 triggers to persuasion and captivation.
A good primer, if you don't know anything about inbound marketing, is the Inbound Marketing book by Brian Halligan and Dharmesh Shah. It covers the basics of what it is and how to use it to get leads and sales.
Now, since David Meerman Scott wrote forward for the Inbound Marketing book I just mentioned, I do want to recommend his book as well - The New Rules of Marketing and PR.
This should keep you busy.
What are your channels? What are you selling? How long is your sales cycle? The answer to your question is much different for the guy selling $20/month subscriptions (e.g. Constant Contact) versus IBM Global Services selling $100 million IT outsourcing deals. They are both B2B but are much different.
Anyone who jumps at an answer here without knowing these answers is missing the point.
Here's one thing to remember with B2B... "prescription without diagnosis is malpractice"
"B2B A To Z: Marketing Tools and Strategies That Generate Leads For Business-To-Business Companies"
"Inbound Marketing: Get Found Using Google, Social Media, and Blogs"
You can also get my free ebook on the topic of How to Turn Your Website into a Lead Generation Machine. You can get a free copy from here