I think it's hard to give instruction for putting, as its all about feel and touch but as for general swing and ball contact (off the green) a couple of things have helped me considerably lately.
You have probably heard of John Richardson but if not, he set himself a target of shooting a par round within 12 months after previously shooting 100+ scores. He kept a diary and wrote a book titled Dream On (a reference to Sam Torrance's response when asked about John's chances) documenting his year ahead and really is a good read. A couple of things I took from his book was the 'anchor', the use of a word or expression which evokes a positive and confident feeling before addressing the ball. The 'clear key' another phrase or term that has nothing to do with golf whatsoever, you repeat your clear key in your head whilst you swing, taking away the chance of any silly thoughts during your swing. Lastly, just focussing your eyes on the smallest, tinyest point on the back of the golf ball and nothing else. These 3 things have helped me loads in the last couple of weeks.