सेवा or service or selfless acts should start from your nearest peripheral activities (bottom up approach). If we directly jump to समाज सेवा/राष्ट्र सेवा, we may succeed but the success is not reflection of our full throttled capacity. Why waste our efficiency? And if we fail, the frustration will keep us away from selfless work.
Go step by step.
Start with your body. Service to Body. Keep it fit and healthy. Keep it away from laziness, lethargy and procrastination. Play sports. Do exercise. Eat fresh food.
Take care of your senses. Save them from indulgence traps (Bollywood, Cricket, Lust, Food cravings)
Take care of your mind. Let it not engaged in useless thoughts.
Take care of your intellect. Stop intellectual involvement in devilish plans to destroy others, office politics, pastime debates, gossip etc.
Let there be no attachment with your work. Work for the sake of work.
And when all of above are serviced selflessly, work for family, society and Nation! See the difference! Experience true fulfillment of life!