The secret of successful cartotanking is in the juice delivery from the tank to the heating coils.
Multiple factors affect this. The thickness or viscosity of the juice is one. Heavy vg ratios can be a bane to carto as well as clearo tanks. Vg can be extremely difficult to wick. With some juice vendors that actually mix each individual order, you can ask for a thinner base for easier wicking. But that doesn't help your current cause.
You may try diluting the juice with some distilled water, possibly as much as a couple of drops per ml of juice. Experiment, I don't believe you'll hurt anything by adding more. Other people recommend diluting with vodka.
Are you punching your own cartomizers, or buying pre-punched? How many holes are you using with this juice? I've personally gone away from punching my own carto's for the most part. I found that with the punch tool that I have (Siam Mods model sold by Phiniac) causes the carto to get out-of-round, or distorted, and can be extremely difficult to get through the endcaps of the tank. That can't be a good thing for tank's 0-rings.
I buy prepunched cartos for my tanks. I get consistancy that way and don't worry about distorted cartos anymore. I order a variety of holes, generally one and two holes are adequate for my juices. I use a one hole for typical 50pg/50vg mixes, and the two hole for anything with more than 60% vg. I've not used the three hole cartos when available, but heard that they can flood easily. For extremely thick juices, tho, it may be what you need. You might consider slotting your cartos if you have a dremmel tool already, if not, its not worth the expense of buying one just for slotting cartos.
I've also switched from dual coil cartomizers to the single coil. I was often tasting some burnt taste with the DCT's, and after doing some reading up on this, decided to switch over. Since switching all of my cartotanks to single coil, I've not had any burnt taste, I get the same vapor and flavor, but I also have noted longer battery life on my mods, which is an added plus. I get mine here, should you be interested:
Single Coil XL Tank Cartomizer for the SmokTank XL
I do have a tank full of Boba's Bounty. It is notorious for being an extremely thick juice. I have triple punched my own cartos and slotted them with a dremmel tool, and diluted the juice with distilled water, and it still has a stiff draw after the first tankfull. Thankfully, its not one of my favorite juices, and is only vaped on once in a great while.
Since you admit that your are new, I always recommend cartotank users get a Slap Yo Momma tank tool. What's this you ask? PBusardo exlains it best:
Buy one. It will be the best investment you make in vaping. Good luck and happy vaping.
Edit to add more comments: I have a few of the Vivi Nova tanks that some of the people have recommended. They are easy to fill and clean, but with some of my juices I noticed some muting of the flavor, confirmed by using the same flavor side-by-side with a cartotank. Your results may vary. They use a wick of silica not unlike the polyfill of a cartomizer, so they are prone to the same wicking issues that a cartomizer has with extremely thick juices. The same is with clearomizers. You will note that they will vaporize the lighter, thinner parts of the juice and leave behind a progressively darker concentrate in the bottom of the clearo tank
--Baditude