I have a rating of about 1850 and I think it's almost impossible to go higher than that without a coach AND hard work. Books can help , of course , but they are not enough. When I reach 1850 I get crushed by higher rated people and I move back... The same happens to tactics... 1850-1900 and then back because of failures.
The same thing with Blitz (bullet is a complete disaster for me because of my tablet pc and slow connection).
Bridging the gap between the intermediate and the master level is just not easy...
2.Heisman's Improving Chess thinker to see how class A and experts think differently and how to better emulate them. Also evaluate flaws in your own thinking process."
This is also the way Silman writes in his books and it is highly regarded as a good way to take a given position and see how players of differing strengths see (or don't see) how to procede. I find it very helpful as well as interesting reading.