If you end up using a hiab where you are standing on the road to operate the controls (you must always stand on the opposite side to where you are dropping the load) then extend the roadside leg right out. I speak from experience because if you try to be “nice” to the cars trying to get past you, they will take you out at 40 mph ! It’s better to make them wait and be safe.
Also, don’t ever put the boom out over the cab to drop a load - if the hydraulics fail, you crush the cab.
Always unfold the crane from the opposite side to the “elbow”. I know someone who did it from the wrong side, and the crane jumped up and nearly took his head off.
To prevent the truck tipping, always lift the load, then bring the load in as close to the crane as possible, then swivel and then extend.
Don’t forget, as you take weight off the wagon, adjust the legs to take up the slack, and drop the air suspension right down before you put the legs down.
If anyone on site wants you to put a load directly onto a scaffold loading bay, either ask for the certificate for the loading bay and refuse if they can’t provide it, or ask them to sign a disclaimer stating they asked you to do it. If in any doubt, don’t do it - phone the boss if you’re concerned.
Watch out for those wires !
Don’t use the crane if there is lightning overhead !
If anybody tries to walk under the crane or the load while lifting - stop. Don’t proceed until they are clear. Keep an eye open so that you can stop before they get near the lift, and better still get a banksman to keep people away.
If you are using strops - check the label on the strops. They legally have to be tested for the load weights you are lifting and they expire ! Any damage to the stitching can make them illegal to use.
Always make sure the eyes on the strops are completely inside the hook and the clip is closed.
If you’re lifting long loads (packs of timber/steel) attach a rope to one or both ends, and get someone to help guide the load and prevent it swinging.
If you are using strops on pallets, and the load is smaller than the pallet, try to get the strops threaded through the pallet as close to the load as possible - otherwise the pallet edge can collapse and tip the load.
If you are using strops on delicate loads, use corner boards to protect the product from the strops and spread the load.
Most places want you to stack as high as possible, so depending on the size of the loads don’t go higher than 2 high unless you’re still below head height and the load can support it, but maybe 1 more if you bridge it across two stacks.
If you’re lifting packs of timber, put the strops on the other side of the furthest bearer your strops will reach, equal both ends. If there are no attached bearers, then thread each strop through itself and only attach one end of each to the hook . Pull the strops as tight as you can around the load before you lift with the crane.
A lot of those might be obvious, but some things you find out as you go along.
Another silly thing is - check the controls everytime you use a crane. I’ve used cranes which have been identical in every way, same make, same model, same type of truck, but one control is reversed ! I had this on a brick grab crane once, one foot pedal is extend retract, and the other is open or close the grab. Guess what happened when I “extended” a load at about 5 foot in the air !
Another thing about brick grabs - if you’re lifting pallets, then as soon as you can see the pallet, spin it to make sure you have grabbed it properly. If you’ve missed a bearer on the pallet, have another go. Sod’s law says you’ll lose it while it’s in the air otherwise. Depends on the weight of the load of course.
When the grabs finished with, put it on the deck and strap it. Don’t rely on it’s weight to keep it there. Even if you grab a full pallet, still strap it. I always have an empty pallet with my nets on which I put the grab onto then strap over the lot - comes in handy when loading, just undo the strap, chuck both ends on the pallet and lift the lot up in the air out the way.
If you have to unload on a hill, then try to arrange it so that the crane only has to slew downhill, because it’s a pain having to stow the crane and turn the truck round because the PTO can’t provide enough power to swing uphill.
Sometimes they’ll load the wagon with heavy stuff right up the front. The crane won’t lift it properly from there, so just lift enough to take the weight, and retract the extension to drag it closer until you can lift it safely. Of course that’s no good if it’s your first drop and the bed is loaded, so arrange your drops accordingly.
Another obvious one - always do a walkround check after stowing the crane and preparing to leave the site. I know a guy who drove for about a mile before he demolished a bus shelter with his nearside leg ! Good job the shelter was empty. Make sure all the safety pins are fitted too, especially on older type legs that are manual pullout.
Make sure the throttle for the PTO is working properly. A bit of wood holding the foot throttle down is not safe !
I’ve found that if you look after the machine and don’t thrash it, check oil levels, check the pipes for leaks, and generally keep an eye on it, then it will stay safe to use. It was always first job of the day for me, before doing any drops. Fire the truck up and do a dummy run with the crane, legs out, the whole thing. Only takes five minutes and saves turning up on site and having to handball the stuff off 
I think overall, the main thing is to take your time, and think about what you’re doing before you actually do it - plan each lift. Don’t rush, especially climbing up to the crane seat, or jumping off the bed of the wagon. One slip and it could all be over, and no job is worth your life (or anybody elses).
