You will have multiple goals when trying liquids, and (in my opinion), this is the order of their importance:
1) You will want to determine the nicotine level that is right
for you. That may have very little to do with the type and amount of cigarettes you smoked. For example (if memory serves me correctly), Xanax and I need the same 36 mg. (uber-high). He was a half-pack-o-lights smoker, and I was a 3-packs-o-Kools smoker. Most people are happy between 12 and 24 mg.
2) You will want to find a few flavors that you LOVE, that really blow your skirt up. Flavors that make you think "why in the heck would I ever want to smoke one of those nasty cigarettes, when I could be vaping THIS?!"
3) You will want to find out about your PG/VG ratio preference, if any. PG gives you the "throat hit", the harsh feeling you get when inhaling. VG makes thicker, more visible vapor. Everyone is different, and preferences range all over the place between 100% PG and 100% VG. My guess is that 70-80% PG is most popular, and 100% PG is most available. Just to keep things interesting, your preference is probably going to change over time as well.
There are probably other things to consider that I'm not thinking of, but those are the primary things you should keep in mind when trying out juices. None of us are shy about naming our favorite vendors and flavors, but most of us also know that it is mostly subjective. I loves me some TV Butter Rum (tastes like a hard candy, Lifesavers or something) from tastyvapor.com, along with their Atomic Cinnacide (in small doses, it's a very strong cinnamon-candy flavor like Red-Hots or Atomic Fireball). The problem is, he does not sell sample sizes, because each 1 oz. (30 ml) bottle is made to order and custom-blended as per customer request. It's great stuff, but I
hesitate to recommend that you try him
first, without any idea of your own preferences. There is a co-op thread
here, but they are ordering zero-nic (just trying out the flavors). That may change on the next round, though.