If you have rented an apartment or house, you will need to give notice to your
landlord of the date that you intend to vacate the property. If you paid the
utility bills directly, advise the utility companies in writing of your departure
date and arrange for meter readings so that the final bills can be drawn up
and settled before you leave. If you paid your bills by standing order, it is
advisable to cancel these with your bank, in order to avoid any incorrect debits
from your account.
As you needed to complete forms when you left, you will need to fill in forms
when you return. The easiest way is to contact the consulate where you are registered
to sort out your situation.
You will have to establish a fully detailed inventory of your furniture. A
moving form attestation is often demanded when you pass the border (you can
ask for it at your Consulate).
You will have to think about school registration if you have children.