Recently, I've been working with the principle of "ishwara-pranidhana". The last of Patanjali's niyamas is usually translated as "self-surrender" or "surrender to the Lord". This is a hard one for many modern yogis, many of whom don't seem to be inclined to surrender to anyone or any teaching.
You may feel that you do not relate to the concept of "God" — or that you do not really know who or what God is — or even whether God really exists. You may (understandably) be loath to commit to doing things that you don't understand, even though they have been advocated by both ancient scriptures and modern yoga teachers.
If this is your situation, it might be helpful to envision ishwara-pranidhana as the steps you take towards letting go of your self-imposed limitations. You might begin by looking at how much your world is created by your thoughts. For example, when you tell yourself that you are weak, you will probably find yourself lacking strength. Or if you focus on an emotional experience, such as grief, it begins to form an integral part of your personality.
Begin by being a "silent witness" and seeing how you mould your character by your thoughts. The more you hold on to negativity, the more it controls you.
Remember, it is only the thought that you are not free keeps you from being free.
with best wishes for great success in your sadhana