An excellent method of determining the price at which a trading instrument will become overbought/oversold is to link up with a counter-trend trader and ask the price at which they placed their drop-dead disaster stop. That's where price will reverse 95% of the time If you trade the ES, emg on ES Journal is one helluva overbought/oversold indicator, usually calling price turns within 1-4 ticks well in advance, giving you ample opportunity to trade your way to the pivot, where you can then stop and reverse.
I think in terms of past ten day average range for starters, say it is 12 points and from today's low we are eleven points, this will certainly alarm me as possible end in trend. Then I also use volume for ES, using a couple different timeframes of 5/3 minute and 5 second bars. Then also distance from one pivot high to next pivot high is decreasing (this price action will often give just about any indicator divergences). On solid trend days, some indicators will be OS/OB all day long, so using so many divergences in a row, one could stop using an indicator altogether. Every market has it's own personality, and each timeframe can also have different extremes. Nearly 90% of the trades I do in ES are counter-trend, but I am a scalper. I can do what I do in ES and do very well, but doing the exact same methods in the ES will not work in a market like crude oil cause this market is totally a different animal as it really trends and ES is a congestive market.
when I do counter-trend trading, I use intra-day support/resistance as my overbought/oversold indicator normally the market is in an range or in an consolidation phase. you may take an example of sweetcrude's 3/23 intra-day chart in other case, I use the distance between my EMA and the current market, if 1'minute chart, in crude, 30ticks+, if 3 minute, 90ticks+, in matter of fact, I just use that for quick bucks, catch a big trend's counter-trend little pullback move,then quickly flip over to catch the big move.for newbie, better avoid catching the counter-trend littel pullback move, you need be fast fingers, very risky if you hesistate
I don't know what the most commonly used ob/ov intraday indicator is , but i use a 1 day Standard Deviation as a guide .
Just make sure that you choose the timeframe that everybody else is using. (that's humor) The problem with oscillators is that everyone else needs to play along as well.