What is the best way to learn forex trading

Learn to trade; practice and test different strategies using a demo account; start trading real money using little capital; learn to control your emotions and be as objective as possible while trading on the real account; when you reach a point where you have experience with your strategy and can control and manage your risk and emotions to earn profits consistently, it will be your decision to increase your trading capital. Here's how I evolved in trading forex:

December 2012: Learnt forex trading basics
December 2012 - February 2013: Demo account practice
February 2013: Started trading on a real account
March 2013 - October 2013: Period of inconsistency (alternated between trading strategies, emotional inconsistencies etc.)
November 2013: Discovered a technical indicator and personally researched on its profitability by studying the percentage of signals from January 2010 to December 2013 that were successful.
January 2014 - present: Consistently using a single technical indicator on a single currency pair (GBP/USD) and making profits consistently.

Test or do some research on your strategy. For example, my indicator, from studying its 3-year signal history, shows that for a TP of >or= 40 pips, the probability of success (per trade) is 81%. For a TP of >or= 50 pips, the probability of success is 74.8%. For a TP of >or= 60 pips, the probability of success is 67.4%. Using a risk to reward ratio of 1:2, I selected a constant TP of 60 (p=67.4%) and an SL of 30 (1-p=32.6%). The reason why I selected TP 60 even though it has the lowest probability of success is because the SL of 30 gives price a larger range to course through.

That was just an example of objectivity and emotional dissociation. Be as objective as possible and don't fall for behavioural biases (it also helpe greatly to study behavioural finance and be aware of trading biases, so that you can detect when you're experiencing a bias).