People use ADX indicator to look for trending or sideways market. I tend to keep it simple. Just plot the ATR in the time frame you are trading. When the market is sideways we have small candles (hence small ranges). Smoothen the ATR with a say 10 period moving average and see the levels from where it rebounds over a few days. You will yourself realise after seeing the results as when to expect good trends intraday. (When market is sideways, the ATR starts coming down till it reaches a low which is fairly constant everyday)
Anyway..