In simple terms role of Open interest in derivative trading is similar to the role of Volume and stock trading. For stocks, if price move is supported by Volume then it is more reliable. You can interpret OI in the same terms for the direction of F&O price move.
Difference between Volumn and OI -
As there are many strategies available in derivative mkt - like buy call at price A and sell call at Price B for same month, buy call at price A for next month and sell call at price B for current month etc, the OI value may not give very clear message in reality. Hence it has to be looked carefully keeping in mind its limitations.
It does help in assessing sentiment but sooner or later, everything gets reflected in Price. So if one pays attention to the price chart and uses Technical Analysis then that should help in taking investment/trading calls.
Happy Trading.