Before entering the market as a trader, you need to have a plan on what you want to do and how you plan on achieving it. You need to make decisions based off of information you have collected to execute your trades. You need to have a plan on how to gather this information and utilize it to your advantage. You must know what information you will need to make the appropriate decision on entering or exiting or exciting a trade. Some people choose to look at the underlying fundamentals of the economy as well as a chart to determine the best time to execute the trade. Others use only technical analysis. Whichever methodology you choose; be consistent and be sure your methodology is adaptive. Your system should keep up with the changing dynamics of a market.

Yes it is very important to have a plan. It gives you a better idea how to move forward. The plan should be devised carefully following previous trade results and experiences so that it will be taking into account what took place and improve your performance in the future trades. The plan may need to be updated from time to time to remain relevant and take into account changing market conditions.