Well in this case , i think maybe you lack some trading knowledge . You should do some research
, try to identify price movements and market trends before placing a trade. Keep a track of news, newspapers etc which will provide you some really informative knowledge. As far as your fears are concerned , take a moderate level of risk and choose your stocks wisely.
Practice will make you better. I would recommend you to try DEMO TRADING for practising as it will help you to test your trading strategies and familiarize yourself with the features of a trading platform. Once you are confident enough about your trades , start trading on a real account.
Never lose hope . You will surely master this game some day but it will take time. So keep calm and keep practising.