Planning beforehand will give you time to ponder about your skills, talents and abilities and help you decide for yourself what you wish to achieve in life. Set a target for yourself and aim at it with vigor and you are sure to achieve success.
Secondly, most of us make the mistake of misjudging our own potentials and often people are found to have high opinions about themselves. The end result is dismal as success eludes them. Mere setting of improbable goals will only make matter worse. You must never aim for things that will be beyond your capability.
Thirdly you must try to start on a career that will give you complete satisfaction. Job satisfaction is a must if you wish to stick to a profession. You can achieve success only if you are able to find interest in your daily tasks and this in turn reflects on your performance and success becomes obvious.
So choose wisely when it comes to making a lifelong decision like career which will have serious impacts on your future. Impulsive career choices can be baneful. Often we find that parents enforce their children to take up professions which they like. This is a grave mistake as most of them are unable to stick to the profession that have been thrust on them and hence most are found quitting jobs after a year or two. Quitting jobs every now and then has serious impacts on their career graphs and they lose credibility. So do what you like to do as it will be in the best of your interests. Being practical is the recipe for success.