Ditto what the others said about starting with a medium nic solution and working up or down as needed. I was a 2+ pack a day smoker (American Spirit menthol), and so I assumed I should start off with a high concentration. I got a wicked headache and some nausea, and eventually figured out I was taking in too much nicotine. (I vape more than I smoked.)
Stepping down to a medium caused the headaches and nausea to magically disappear.
Like folks have said, your body will let you know. For me, I vape mostly low and medium liquid, then spike with a higher nicotine concentration when the cravings start. Works great for me--I've been off analogs since the end of January.
Personally, I think too many newcomers start with too high a nicotine concentration. For most of us, we tend to vape more than we smoked--we can vape in more places than we smoked, we're distracting ourselves from our desire for an analog, and/or we're enjoying a new toy.

I also think that not everyone absorbs nicotine with the same efficiency so that for some, more moderate doses may not come even close to satisfying while for others, it works just fine. I also wouldn't be at all surprised to find that the model of e-cig may play a part--perhaps warmer vapor may promote better absorption. Who knows.
But if you listen to your body, you'll rarely go wrong.
As for the tobacco flavored liquids, the only ones that I've found that taste analog like are Janty heavy shag/cigar. Other tobacco flavors taste good to me, but they have a sweeter undertone than analogs. The longer I've been vaping, though, the better those sweeter tastes seem to me. Basically, I've decided that I don't really care for the taste of cigarettes, so my days of trying to find the "perfect" liquid that mimics my former tobacco habit are a thing of the past.