After a good year of mixing, these are my best tips. . Using weight instead of measuring liquid is far easier and more accurate. . Koolada is magical I use it as often as I can . The base is the bulk of any mixture and usually is a pain to put into the bottle. Basically once the flavors and nicotine are in, I just pour in the base (glycerin/PG) into the bottle using one of those bottles they use to put ketchup or mustard in that you can find in some restaurants, with the pointy tip. Very cheap to buy on ebay. Since I go through 100ml a week, I have to mix at least two 50ml bottles a week and this saves time and mess . Don't overbuy in the beginning. And really look at the reviews before buying. For example, theater butter popcorn looked magical I bought 120ml of concentrated flavor which turned out to be fairly evil tasting, I should have read the reviews first. But do mix things yourself. Cost of 50ml for me is about $2 to mix myself. I think it's what about $10 or $15 bucks if you buy it premade these days? Plus, you're the boss of what goes into it.