Contributors to what is called throat hit:
1. Nicotine content (higher produces more TH)
2. Vapor temperature:
a. Voltage to cartomizer or atomizer (higher produces more TH)
b. Cartomizer or atomizer resistance (lower produces more TH)
c. Wattage of cartomizer or atomizer (actually, this is a product of 2a and 2b)
3. Relative percentage of propylene glycol USP in juice (the higher, the more throat hit).
Honestly, I haven't played around with the variables enough to tell you which of the three elements is more important.
This post is spot on.
1.) If you aren't getting enough throat hit, the first thing I would change is the amount of nicotine in your e-juice. Just get a really high level like 24mg and a zero mg nicotine bottle of your favorite flavor and adjust the proportions to find what suits you the best.
2.) Low resistance & high voltage!! Lowering the resistance of your atty/clearomizer/carty or increase the voltage of your battery accomplishes the same thing and increases both throat hit and vapor production so this is probably the next most important thing to try. I've played with 1.8ohms and 2.4ohms and the different between them is very significant. I would suggest getting something like the vivi mini nova clearomizer if you have a eGo type battery (as they come w/ 3 different resistance: 18, 2.4, and 2.8 heads) or an eGo twist that allows you to adjust voltage if you are looking for a new battery.
3.) The type of system that you are running that the quality of it: cartomizer with polyfill, clearomizer with wicks, or 3-piece atomizer system. I have personally noticed that clearomizers seem to give better flavor, vapor, and throat hit in my personal opinion. I have heard that direct dripping onto an atomizer has really great taste and throat hit as well but I have never tried it. In my experience, cotton-filled cartomizers seems to have the weakest performance out of everything. I would say that clearomizers are the newest and best e-cig tech. The one I would recommend the most is the mini vivi nova clearomizer (very reliable w/ no leaking, easy to clean and replace out parts). I have also tried the vision stardust clearomizers and they do work, but I do prefer the mini vivi novas.
4.) The PG/VG ratio. This does affect throat hit, but honestly I do not think it makes a big difference. I have tried 60/40 and 70/30 ratios and honestly, I cannot tell which is which. PG is very important for flavor and throat hit while VG is vital for vapor. I think that you will only see a difference if you significantly change your ratio, but I feel like both ingredients are important for a good vaping experience. This is the last thing I would fiddle with.
X.) Flavor should NOT really impact your throat hit and if it does, then I would think it would be more of throat irritantion. Darker & heavier liquids do seem to be fuller & heavier smoke, but the difference is very slight and would not be something I would look into changing when searching for your sweet spot. Also, note that strong spicy/cinnamon/citric/acidic flavors can leech the plastic of some clearomizers, so you may want to purchase metal tanks when trying those flavors. I have heard that grain alcohol, cinnamon, capsaicin (ingredient in chili peppers) and menthol ingredients enhance throat hit. However, I believe you should be able to achieve a good throat hit regardless of the flavoring.
Honestly, I think you should be able to find a good throat hit by adjusting the first 3 factors. My experience finding my sweet spot, I find that nicotine content makes the biggest difference and lower resistance/higher voltage also has a very significant impact.
For example, 18mg nicotine was barely good enough for me using the mini-cigarette clones: using standard resistance 2.4ish cartomizers on a 2.7-3.3V battery. On a low resistance 1.8ohm clearomizer w/ a 3.7V battery, 18mg gave off too harsh of a throat hit, and I use about 12mg of nicotine. I am personally trying to lower the amount of nicotine I use because nicotine is bad for the body, so I would personally recommend for you to try lower resistance first. Then mix 24mg and zero mg nicotine in different ratios and see what is the best for you.
Please note that the vapor for e-cigs is different from the smoke produced form a real cigarette. Cigarette smoke has whole tobacco alkaloids, carbon monoxide, tar, and other chemical that produce a heavier, fuller hit. It may be that your body is not used to the lighter feeling of vapor. It does take a bit of time to adjust too, but it is definitely possible for you to find the perfect mix of throat hit and vapor production!!
Don't give up, good luck & happy vaping!