How Hinduism/Sikhism and Islam are/could be COMMON for meditating on NAAM(Name of God)?

Meditation does not require any particular phraseology. The basic things which are helpful in this is enthusiasm with which you meditate, the concentration and the sincerity you put in your worship. For self-realisation and to reach to that 'truth', it is important that you do your meditation with non-attachment, being pure and truthful in your prayer. NAAM could be through chanting but that chanting should spring from the heart and not from your brain. Initially you require some effort in this endeavour and slowly but surely your efforts will fructify and you will be able to connect with Him. This is not acquired overnight. To reach to that Truth, mere words are not sufficient. Urge from your personal being should spring up and transform you thoroughly. Follow any religion to reach Him, but that way to the Ultimate Destination is only acquired through self-purification and with oneness of purpose. Tongue recitation initially and then realising Him through concerted concentration (inhale and exhale concentration) on the centre between the eyes till such time you get light and ultimately peace.