Here are some tips I hope you can use.
Tip #2 - I've found the most reasonable and nicely scented candles to be the ones at Wal-Mart here in the U.S. They're about $5.00 for a big one, a nice variety of scents, burn clean and scent the room. The bonus is they have lids and I can use the containers for other things after the candle is finished.
Tip #3 - I bought this wick trimmer years ago and I don't know what I ever did without it. One of the secrets of keeping your candles from "smoking" is to always trim your wick before you light it. Before I had my "wick trimmer" I used to grab a kleenix and grab the wick and turn and the burnt part would come off leaving about 1/4 inch of wick remaining.