Making sure that your goods are properly prepared for long-term storage means that you can be fairly sure that they are going to be returned to you in good condition. When your moving company comes to collect your possessions it will simply load them into a container or onto a truck and store them as they find them; therefore, you need to do as much preparation as possible.
If you want to store your bicycle then you need to make sure that it is protected from rusting. Make sure that the chain and the derailleurs are lubricated and you might want to consider taking off the seat, as this will stop it from binding to the frame. You might need to put old tires on the bike or prevent any pressure being added to the current tires so that there are no flat spots as the air escapes. You need to be aware that if your moving company storage facilities are not climate controlled then the risk of rust is higher; therefore, you might have to be prepared to replace parts such as the brake and gear cables.
The good news is that if want to store items such as plastic furniture in moving company storage then very little preparation is needed, as these items are not susceptible to damp. All you have to do is make sure that such items are clean, wrap them in plastic to protect them from dust and dirt, and they will be ready for you to use when you get them to your new home.