Self Improvement Made Easy

I'm about to enter a new career in sales and I have a huge collection of all kinds of motivation/self improvement and sales/negotiation training materials. Audio, video and books.

However, in the *real* world, what have people found to be highly useful and workable? If you are a high achiever sales/negotiation wise-what if any would you recommend to a newcomer?

I'm looking at business to business telesales as a starting point and hope to add face to face relationship building as I progress.

At the moment I've a list of authors a mile long and I've listened to a fair amount.However having not field tested it all, I could be in fantasy land as to would work .

Thank you in advance for any assistance. UK based
I do like Frank Bettger's book. I acquired this off an old business pal of mine. Charming and sounds realistic. Dale Carnegie is another I do like.

The other recommendations are appreciated as I hadn't yet seen them. Thank you.
Thank you Ken. John Maxwell I hadn't come across either so far.

Covey, I have his audio which I listened to twice a couple of weeks ago whilst doing a fairly long hands on job. I have his book, that I'm using to revise what I heard .