First things first, when designing a stop strategy you have to bring yourself back to the notion of probabilities and that all we are working towards is trying to find an edge in this market - not an infallible solution. With that back in the forefront of your mind it is then hopefully possible to come up with rules for stop losses which focus on both controlling losses and allowing a suitable margin to keep good-trades running. Finding this balance is key, as the long, arbitrary stop is the friend of the 'holy-grail' trader who cannot bear a loss but will ultimately fail as they take too many huge hits in trying to find perfection in their trading plan. A perfect, save-every trade stop does not exist, but the trader who finds a stop strategy that truly suits their style and keeps their losses proportionally smaller than gains will always have a chance in the long run.
Where this stop lands is completely different depending on how you trade but I think it is just as important to have very clear rules and guides in your trading plan as to how you place a stop as to how you find an entry. There is no hard and fast rule to placing stops, just as there is no set rule for finding profitable entries - there are infinite ways to enter trades and just as many ways to manage them. It is down to your own strategy, how much risk you can accept and how you wish to trade. Gifro, you are quite right to highlight the horrible event of getting stopped just prior to the market moving as you had expected. I think the best way to handle that is simply to make sure you have the stop in the 'right' place according to your trading plan, at least the feeling of having done-all-you-could can only help you get ready for the next trading opportunity.
I had a very average day yesterday but it felt like a good one because on the road to my single, modest win my trade reversed to within ONE PIP of my stop - but held in. Now, this was not a particularly short stop BUT it was in the correct place - both by my trading rules and by the market and that made a small trade feel like a week-maker.
Look forward to hearing everyone's thoughts on this subject...
BM