Per-service lines
One line per service, not one lump sum. 'Consulting (3 hrs)', 'Copywriting — 2 pages', 'Hosting — April' gives clients something to approve and saves back-and-forth.
Recurring billing
For monthly services, duplicate last month's invoice and change the number and period. The generator remembers your draft in this browser — the fastest possible repeat bill.
Disbursements
Travel, printing and software bought on the client's behalf belong on their own lines marked 'disbursement', tax-free in many systems.