To pinpoint a trend reversal you need to be absolutely clear about what is a trend - seeing some upward price movement does not always mean you are now looking at an uprend.
More than that you need to identify which trends and which reversals are useful for your strategy - a sudden counter-trend price movement does not necessarily mean the original trend is broken or that a new trend is now starting.
I am mostly a trend-follower, I only take reversal signals like Smash Days (Smash Days in forex).
For trend-following, I prefer to be on the long side of the main US indices and not right now - only when they are consistently rising. But in all cases I want to see price moving upwards from a recent swing low which is above the previous swing low. This means I am entering on at least Day 5 after the reversal, often later - from the bottom reversal or swing low I want to see 2 days up to a new swing high, then 2 days down to a new swing low (higher than the first one) and I will set a buy order at the high of Day 5 if it closes above the swing high.