correlations of different markets has been beaten to death by many, including the computer quant geeks. If there were still obvious ways to make reliable money from this, they would arbitrage the hell out of them.
...sorry...STOP...is not in my vocabulary...when it comes to trading...I am RELENTLESS in the pursuit of the PERFECT trading system...yes, I believe there is one!
Unless you have inside info, there is NO WAY TO CONSISTENTLY PREDICT THE DIRECTION OF THE MARKET prior to the open!!!!! STOP being lazy and put in the necessary screen time. Learn the game, STOP looking for the quick and easy fix. Learning to read the market takes time, there is no magic formula you plug in. Its all about you learning the game through hours and hours of repetition. If you arent willing to do it, you might as well quit now and look for another calling.
Marty Schwartz has said that it is the overnight trading of the cash bond... but this won't help you out. What will really help you is to stop thinking of indicators, of strong correlations, of easy ways out. Some days crude is running, so the oil sector is strong and pumps up the rest of the market. Some days the brokerages report write downs, and this drags the market down. Some days one sector is strong, one sector is weak, and the market is neither. It is all connected, and at the same time it is not. I used to have biases on what the market will do based on certain macroeconomic forces, and my losses showed it. Now I just follow the market, if it is acting strong, I will look to buy; if it is acting weak, I will look to short. I am a new trader, less than a year, and this month I have profit of $8000 so far. My point is, there is no holy grail to trading. If there was, wouldn't we all be doing it? There is a tip though: Trade what you see, not what you think.
There is no best one thing that indicates US market direction for the day is. If there was we would all agree on it and use it to predict the market and we all know how difficult that can be. Better to hear the truth than hold out for a fantasy .