As you start on the path...
"First train in the preliminaries" (Atisha mind training slogans)
Before any serious transformative practice is undertaken, the mind has to be steadied and turned toward the goal.
This is done by adopting a suitable lifestyle and following some guidelines on ethical conduct.
In Buddhism, these preliminaries are covered, mostly, by the precepts, and in yoga, by the yamas.
The first and most important guideline is non harming (called Ahimsa in yoga).
These means that any spiritual aspirant make it their top priority to abandon lines of conduct that result in harm to any kind of living beings. This may entails a change to a vegetarian diet, but also a change of job (if your current job is connected to the meat or arm trade, for example)
The second one is right speech (called Satya in yoga).
This means not just abstaining not just from lying but also from slander, abusive or harsh speech and gossip or frivolous speech. Master Gautama describes right speech as timely, true, gentle, beneficial, and kind.
The third one is abstaining from taking what is not freely given (called Asteya in yoga).
The fourth one is wise use of energy, particularly sexual energy (called Bramacharya in yoga). Using sex as entertainment, as we often do in our Western culture, is not an option for anyone on a journey of self development. An aspirant energy should be directed toward the goal of living a more useful and more fulfilling life.
Buddhism recommends complete abstinence from mind altering drugs, while yoga recommends non attachment (Aparigraha). Both practices are most useful to achieve more peace of mind.
Just imagine how different the world would be if everyone followed all of these guidelines, or even just one of them!
To follow these guidelines consistently, a certain level of mindfulness is necessary, and cultivating this is also one of the preliminaries.