Apart from teaching of our beloved guruji Paramhansa Yogananda I found the meditation technique "transcendental meditation(TM)" of Maharshi Mahesh Yogi and "sudarshan kriya" breathing technique of Sri Sri Ravishankar very useful. Can I practice these techniques? Is it useful??
—dhruv parikh, india
There are many different spiritual paths. A true spiritual path will lead you to oneness with God.
Once you have found your guru and taken a vow of discipleship, you should follow his spiritual path with all your heart, mind and soul.
Paramhansa Yogananda gave a complete set of spiritual practices to lead you to God. If he is your guru, you need to go deeper and deeper into the different practices that he gave, read his teachings, practice them in daily life, and give all your devotion to Him. The more you will immerse yourself with the spiritual practices that he gave, the more you will feel their power and you will be transformed.
In that case, it would be best to set aside any other meditation techniques from other teachers, and dive into the wealth of what P. Yogananda gave.