The biggest problem most seem to have is - aside from selling into fear, if you are not vested - you do not have fear of loss. Ever.
One tactic one might take is 'pretend' you are in a stock with X shares prior to entering a position. If one can 'feel' the raw emotion of what it is when they are in it - without risk - then it might help one feel if it is the right time to trade or not.
Of course, one should also review financials / news / charts as well. This was just an idea I've had recently.
News 
Market Data 
Discover 
AI
