First of all make sure that the load is evenly arranged in the trailer. Do not put too much weight on either side of the trailer, as it can cause instability and the trailer might get overturned while being driven. Even if does not cause any safety issue, it is risky to carry an uneven load, it can compromise safety of other people.
The second most important step is securing of the load with straps of binders. Leaving load without binding can make it spread across the road and thus can cause safety issue to the vehicle, the driver and other people.
While driving with a flatbed trailer, make sure you take special care at turns, potholes and curbs. It is better to slow down when you drive around these places. You should considerably slow down at turns, as negotiating with sharp terms at a higher speed can overturn the trailer.
Also be aware of intentions of other drivers. If you feel safe, give them way or otherwise take your time to side your vehicle. Taking your vehicle to one side at a sharp speed can risk a mishap, and this will be detrimental to you, your vehicle and goods.
Use side mirrors to monitor the load. If your load is too heavy and cannot be monitored easily, use your judgement to do so. Otherwise, it is highly recommended to have another person along with you to regularly monitor the load.
If you are alone and cannot monitor the position of the load while driving the vehicle, stop your vehicle at places and monitor the load. In case you observe any change of position of the load, resettle it or tighten the straps, in case they have become loose.
Follow all safety and driving rules while driving the vehicle with flatbed trailer behind. Do not over speed or overtake any vehicle, which can result in a mishap of either of the vehicles and risk an injury to either of the drivers.
You should check if the vehicle has the fuel at right level and pressure in the wheels is good enough. If not, fulfil these requirements before taking the vehicle out on the road.