I've been vaping around 10 years -- when the batteries were activated by drawing on them (no buttons). Anyway, here's a few tips I haven't seen here:
_ I got a few "oral dosage" syringes - (give-aways from my pharmacy). I used them to measure, and with:
_ Press-in bottle adapters/inserts that are made for the oral dose syringes (fit inside a normal size bottle mouth to accept the syringe nipple) - they may be avail at pharmacy but I got mine online. NOTE: I have 2 sizes available if you'd like to have one or a few of each or either - cheap.
_ I started making my own liquid VERY early on -- I've settled on one favorite (LorAnn pina colada, candy flavoring) -- used ejuicemeup's calculator.
_ I also found that whenever my juice started tasting hot (a little "sharp" or nippy in my mouth) I decreased the nic content a little. I still have a lot of nicotine in the only bottle I ever bought, so it didn't take long to get to -0-. I still craved the feeling in the mouth for a while but that decreased gradually - I don't take anything with me any more, but still vape occasionally since I still enjoy it.
_ I made/make up quite a bit of liquid at a time and store it in an glass bottle.
_ I use a regular syringe with blunt needle to fill my atty -- but whatever you've been using can be reused with your DIY liquid.
Hope you have as good luck ditching the cigs as I did -- it was easy as I just gradually stopped smoking (when I REALLY wanted one I had one). My last cig was the first drag in the morning - it tasted awful and I've never had the craving since. FYI before I found vaping I'd tried stopping several times before, including Rx and patches (neither worked for long).