Risk ration is quite an individual thing and every trader is to decide how much money they are ready to lose in every trade.
As a rule, risk percent varies between 1% and 3%. Such a proportion is considered to be conservative enough to secure your budget from the losses cause by occasional fluctuations on the market. I believe that the best way to understand how much risk you can take is to try to open the different deals with different risks and see where you feel the most comfortable. I mean that usrely, all of the people feel best when they don't have the risks at all, but you should also look at the profits. You my have 0.5% risk, but your profits will be too low to keep you motivated. You should start with the smallest risk and watch how much money you manage to make and gradually increase the risk until you feel the fear of losing this amount of money in a single deal.
Unfortunately, there is no point blank answer to your question as it is up to you to decide and understand which trading conditions and environment suits you the most.