Ṛk Veda Maṇḍala 2, Hymn 24, Śloka 1

गणानां त्वा गणपतिं हवामहे कविं कवीनामुपमश्रवस्तमम्।
ज्येष्ठराजं ब्रह्मणां ब्रह्मणस् पत आ नः षृण्वन्नूतिभिः सीद सादनम्॥
gaṇānāṁ tvā gaṇapatiṁ havāmahe kaviṁ kavīnāmupamaśravastamam|
jyeṣṭharājaṁ brahmaṇāṁ brahmaṇas pata ā naḥ ṣṛṇvannūtibhiḥ sīda sādanam ||

Try saying each word group 12 times …8 groups
[gaṇānāṁ tvā] [gaṇapatiṁ havāmahe] [kaviṁ kavīnām] [upamaśravastamam|] [jyeṣṭharājaṁ] [brahmaṇāṁ brahmaṇas-pata] [ā naḥ ṣṛṇvannūtibhiḥ] [sīda sādanam] ||
Then recite the full śloka-mantra 108 times. In this say ‘auṁ’ loudly (long) first and then in next breath say full śloka once.
You should be able to sing this in 10-20 days if you try hard. Remember you have to sing to get results