A lot of people will tell you to focus on your thoughts - check to see if they are positive or negative etc. This is the quickest way to become lost in them. There is no such thing as positive and negative except to a mind cut off from its Source. If you as an ego hold something 'good in mind' it is only because you have an unconscious idea of what is bad, therefore, without even realizing it, you are holding both good and bad in mind - and eventually - as sure as day follows night, your greatest joy will become your greatest sorrow.
Do not focus on your thoughts and try to control them. They are delusions within illusions. The mind without its Source is a maze you will become lost in. Do not focus on the content of your thoughts! Focus on whether they are being given or they are being taken (generated). If you are conjuring or taking thought, then you are in an egoic frame of mind - you are in illusion - maya.
The only way to dispel this illusion is to stop thinking. One does this by focusing their Consciousness on the Awareness of the Moment. Everything you are Conscious of is your Awareness. Your true body. Your Soul. Keep your mind focused there. When the mind is focused it cannot think. Just the same as you cannot think when you are listening intently for someone to say something or when someone truly interesting is talking. Try it - listen intently - focus on someone talking and watch how you do not think.
When you become more interested in where thoughts are originating from rather than what is in them, you will be ready to rise in Consciousness. If you try to control your thoughts now, as a mind cut off from its Source, it will be merely one thought that wants to do good bullying another thought that doesn't. Only one's Source can master the mind.
Once the mind is still, it becomes an instrument for Source - Spirit which will slowly but surely guide you home to Thy Self. Once the master is home the mind will fall into submission.
"The most decisive event in your life is when you discover you are not your thoughts or emotions. Instead, you can be present as the awareness behind the thoughts and emotions."