You work one funded milestone at a time. Nothing you deliver is unfunded, and nothing you start should be.
Before starting
Check the milestone is funded. If it is not, do not begin. The escrow protection you have exists only once money is held.
While working
Post a short update at the halfway point. Clients who hear nothing assume nothing is happening, and that assumption is where disputes start.
If something will be late, say so before the deadline. A client told in advance will usually agree a new date. A client told afterwards will usually raise a dispute.
Scope creep
Requests beyond the accepted proposal are scope changes, not revisions. Say so politely and propose a new milestone. Absorbing them silently trains the expectation and costs you the project's margin.
Submitting
Deliver through Project Submissions. Every deliverable is screened before the client sees it. Delivering by private email leaves you outside escrow with no protection if payment is refused.