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Production longlining is the fast and efficient movement of materials

from one place to another, typically used in seismic work, where you try and drop 30-40 bags full of equipment an hour. This is very often in places where people can’t get around very easily, even without a 250 lb bag, and you will not be popular if you drop the stuff in the wrong place. Although GPS is useful here, many pilots (including myself) prefer to map read and get really familiar with the area before starting. In my opinion, the cockpit is not the best place for your head when buzzing around trees – oddly enough, a little instrument training can be beneficial here, as it gives you the basics for taking in a lot of information in one glance. In any case, the ground crews should mark the drop off spots with an orange X, at least 6 feet in size, with a double one at each end. Ensure your own ground crew have the serial numbers of all equipment you move – this will stop the customer unloading any old junk on the insurance if you have to drop anything.
.  Precision longlining means what it says, and usually involves moving drills, etc. because they are heavy and cannot be moved once they are on the ground.
The real finesse with longlining comes when moving loads that take up nearly all the payload available, although you should never use it all, because you leave yourself with no margins, ether with power or pedals. Some companies (and customers) will expect you to "inadvertently" use more power than the maximum to get the load moving in the first place – that is, it's well known that you are not allowed to intentionally use more torque than that in the Limitations section of the Flight Manual, but you can do so by accident. What you do is up to you, but that margin is for getting you out of trouble, like when a load sucks you into a hole and you need to give it a gentle landing – you should always aim to do the complete job within 100%, which is what performance graphs are for, talking of which, remember that humidity can reduce their figures by as much as 10% or more, so be careful after a good shower. Put more simply, overtorquing (within limits) is for landing, not taking off, but you knew that already. Another consideration is looking after your engine – many turbine failures are the result of pulling too many cycles from minimum to maximum Ng, so if you don't need 100% torque, it's best not to use it. It's also best not to reduce the collective lever to the bottom when descending, either, and to make power changes gently, avoiding over- and undershoots.
It's when an experienced longliner gets on the controls that the whole process becomes like poetry in motion, with the load and helicopter becoming a symbiotic pair, when every ounce of performance is extracted from the machine, even to extent of bouncing a load against a tree to set it in motion (without damaging it of course!).
Naturally, with the top half of your body twisted round, you have to learn some new motor skills. Some people say there is a tendency to pull the cyclic the same way as you are leaning, and back, but I found a bigger factor was the drift that occurs when you lower the collective, which you learn to cope with automatically when learning to hover. To take a LongRanger as an example, from being nicely positioned over the load with a vertical line, and reducing power, unless you make a conscious correction, you will find yourself very much to the left of the load very quickly. It's too easy to accept the resulting parallax position as the normal one and try to take off again with a slanted line, which means a potential for dragging the load.