I've just made my first batch of scented soy candles and they're not burning very well. I used one pre-waxed wick per glass which said it was for candles up to 9cm diameter and mine are a bit smaller than that, so should be ok. I left the candles a couple of days before trying to light, so they had set nicely. Any ideas as to why they're not burning? I've managed to get one to stay alight by pouring off the wax as it melts, but need to use them as presents and desperately want them to look professional! Any advice gratefully received.