I have read and heard hundreds of spiritual and success books, and one success principle that sticks out for me as most relevant and most important is - connection with Krsna.
If you have a problem to solve - first connect with Krsna.
If you have a result to achieve - first connect with Krsna.
And everything will be different. Everything will be more clear, more auspicious, and of a higher quality.
So how can you do that?
Our beloved spiritual master and guide Srila Prabhupada gives an answer:
"We should know in perfect consciousness that human life is bestowed upon the conditioned soul to achieve spiritual success, and the easiest possible procedure to attain this end is to chant the holy name of the Lord."
SB 2.1.12 Purport http://vedabase.net/sb/2/1/12/en1
So the topmost success principle is to always first connect with Krsna by chanting Hare Krsna - in any situation.
From this all clarity will come.
From this all intelligence will come.
From this all courage will come.
And from this all success will come.
You will not be able to believe me if you do not try it and see for yourself. And our Gita Coaching process can assist you with that.