With strong rallies in the American markets, we can assume that the Nifty will have a gap open. A big gap has two possibilities: the gap will be filled, or, strong momentum will take the move forward. The 15 minute rule can be used to control your trades. If the gap is going to be filled, then price has to go lower, meaning that it will break the 15 minute low. Therefore, this low then becomes a stoploss, a selling level as well as a support level. Given today's SGX Nifty price, it may be wise to (a) look for a dip to the 15 minute lows for a buying on dips opportunity / (b) buy above the 15 minute high with a stop below the low.