You are a first-time investor and therefore, it is quite possible that you would not be well aware of the nuances of the market. At such times, you can take help from a professional investment advisor. An investment advisor or financial planner would help you identify and analyze your goals and work towards it.
You can set a target of a profit of 15-20% a year, when you buy shares. You must sell your shares when the target has been achieved. Let’s say you have bought shares and they have gone up 20% or more in couple of months. Your target has been achieved sooner than you expect. You sell your shares as the target has been achieved.