Assuming you have done the fundamental work on the short side, how to trade currently is very simple. This is where technicals meet fundamentals. The trendline falls somewhere around 855 on the S&P. No surprise, the futures indicate an open right around 855. The were down more earlier but they gravitated towards that 855 level as the open came closer. Now 884.75 does not consider a break. I would be on pen needles until you really broke 850.
The other thing that must be on your screen is the Euro. Think currencies doesn't matter, fair enough, I'll for one be watching it. Last night I noticed the Euro was down again very strongly for the fifth day in a row and I was wondering if Europe was going to be able to ignore it again today. Nope, down two to three percent across the board.
The euro dropped to $1.2956 as of 7:21 a.m. in New York, from $1.3044 last week. It earlier declined to $1.2947, the lowest level since March 17. Europe’s currency fell to 127.86 yen, from 129.33 yen, the weakest since March 30.