Oh, another tip from somebody who was a heavy smoker? NJoy. They're too expensive to use regularly but they're high nic (the "bold" are, like, 45mg believe it or not).
Vapor delivers the nic slower than smoke. You'll adjust and your habits will shift around to fit this new thing but at first, you may get those screaming cravings because you were used to being able to get a quick "fix" (like that "ahhh" feeling of the first drag of that first cig of the day?). I found keeping an NJoy disposable around could help. They did a decent job imitating a cigarette. It even feels papery and all. They can be like a quick... oh... "booster shot"?
Also, a year on, I catch myself sometimes missing the whole... feel? You know, holding the cig, taking a drag, the... experience? I still sometimes get a disposable NJoy or Blu when I get that. I guess because it was such a habit for so long, I sometimes need to "play smoke"?
Anyway, varying your nic level is common. I did it back at the beginning. Seems after some months, I settled on a "middle ground" and don't vary the strength anymore but had to at the start. Like 18-24 to start off and after eating. 12 (ish) for coasting most of the day. Around 6 for evening. Especially that last one. I discovered that nic--being a bit of a stimulant--kept me awake half the night. Not bad awake, not like insomnia (which is miserable), just... awake. Alert. Staring at the ceiling until three in the am.
Now I don't bother. I'm around 9 to 11 all the time (I do my own mixes but don't even have to worry about hitting an exact number, "close enough" works now). But at the start? Definitely.
EVOD toppers are pretty inexpensive. You can get extras, pre-fill them, have them ready to go. It can help reduce that "I WANNA REAL ONE!!!!" yelling in the back of your head.
(For me, it was sometimes like having a three year old in the back of my head having a tantrum.)