To be honest, it comes with experience. But for the reference i could suggest you 1 book which can definitely help you in learning this.
Technical Analysis Explained: The Successful Investor's Guide to Spotting Investment Trends and Turning Points - by Martin Pring
Apart from this website like investopedia can also help
http://www.investopedia.com/university/s...
http://www.investopedia.com/university/s...
Try hands on with a virtual portfolio by imagining you have £100,000. Invest £5000 in each of 20 FTSE 350 stocks. A return of above £5150 or 3% will mean a profit.
Library Card
tons of free books you can read
Im a total beginner