If you are having trouble with your focus during meditation then I suggest trying sandalwood powder. The yellow kind not the red kind. You can often find it at places that sell lots of incense or online if you live far from town.
You don’t need much although I buy the stuff by the pound. A four ounce bag of ayurvedic grade (santalum album) for under fifteen bucks. A half ounce for about six bucks.
You don’t need any fancy burners either. A ceramic bowl with some sand at the bottom and some of that easy light hookah charcoal they sell in smoke shops or liquor stores and voilà you are on your way.
It has been used as an aid for meditation even before the time of the Buddha and is still used in monasteries today. It has a way of helping concentration.