As we know, the price does not move up or down like a rocket, it has to take a pullback or a pause. So after a trending day most probably the market stays sideways. As you can see today's market was in a trend and most probably tomorrow it will be a sideways market, and our analysis will be simple if nifty opens above the previous day's high(PDH) market can get resistance from the 17970 level and will be in a range the whole day.
Note - I'm not sebi registered, this is only for educational purposes. Do your own analysis first.