Budget realistically
Rule of thumb: Warm rent maximum 30-35% of net income. Plus: electricity, internet, GEZ (€18.36), liability insurance, contents insurance. Deposit (usually 3x cold rent) must be paid before moving in. Furniture, kitchen, moving - first apartment easily costs €3000-5000 extra.
Searching without income
As student/trainee: Parent's guarantee is standard. Parents should provide income proof + SCHUFA. Submit BAföG notice or training contract. Some landlords accept advance payment of several months' rent.
Shared flat or solo?
Shared flat is cheaper and more social, but conflicts possible. Own apartment gives freedom, costs more. As a WG sub-tenant you often have fewer rights. With the main lease you're liable for the full rent.
Organizing the move
Give notice 3 months ahead (or find replacement tenant), organize moving company or friends, mail forwarding at post office, register new address within 14 days (fine!), don't forget to transfer electricity/gas.