I was planning a large dinner for a work event recently, and while we didn't actually end up using these for centerpieces (we ended up going the traditional route and used a bunch of fresh flowers), I still thought they were pretty cool - especially if you wanted to try something a little different and/or extra colorful. Note that an LED candle is a must here, since a real candle might catch the tissue paper on fire… which would be no good for your event…!
Create flowers out of your tissue paper. I followed this amazing guide to determine what kind of tissue flowers to make, how to cut the tissue, etc (from my Pinterest):
Put an LED candle in your glass jar, and put the tissue paper flower on top. Donzo! You could also make a bouquet of these if you like - what a lovely way to decorate for a party!