A lot of the times when we talk about being mindful, it is about making a conscious decision. We give in to so many things in daily life and we ended up draining our energy and feeling bad afterwards.
A very good way to start being mindful, is not to be afraid to say No. Say no to things you don't feel like doing, say no to things that is unnecessary, say no to drama, toxic situations and people. It is an easy word to say, but not the easiest to do. But once you start to be conscious of what is relevant and in alignment with you, the "no" comes easier, and feel the power of that. Instantly you feel relieved, you feel not obliged to be pressured into any sorts of things.
Set yourself free from unnecessary drama, obligations, social and peer pressure. Start watching your life transform and how to be quicker in making a conscious decision that is best for you without being selfish and self-centered. This is a very powerful way to declutter your life in a good way.