put up a one min. bar....it takes that long for the overnight orders to get filled, you are going to fade the opening gap under the wright conditions ...the one min bar is the open range...in that 1min. the market must trade in the direction of the gap .. if it dont it is no trade...if it does as soon as it brakes the 1 min bar,,, fade that brake out with a market order..what you are doing is trying to catch other traders of sides...the market maker will be trading with you ..they will fade the order side of there overnight orders betting part of the gap will fill,,the risk reward on this is big ..if you are wrong you can not hold on to this trade ,,,you are in a opening drive going at your stop... try it in replay ,,you will be able to tell after 30 to 50 trades if it will work or not very quickly ..like fishing you can tell if the fish is on or not..hope it helps
Keep in mind that opening gap trades in stocks are sometimes only good in hindsight. By that I mean the bid/ask spread is often incredibly wide when the market opens resulting in the first order filled being very different to any orders filled a few seconds later.
A while back I developed an algo strategy based on observations I had made with respect to opening gaps in stocks. It worked incredibly well in my back tests and because I was planning on implementing it algorithmically, it could be applied to any number of opening gaps. However when I started drilling down into tick charts and second charts, it became very clear how erratic those opening gaps were and just how fast many of them closed. If you didn't get the opening tick (or very close to it), you could forget about it. Those trades looked great in hindsight,...but in practice they would never have worked.
It would have been even more difficult try to trade manually.
Anyway, im sure there are profitable gap trading strategies for stocks around,...just be careful of the practical implications of trading them live in the market vs in theory.