Decluttering and a deep clean are the fastest part and the one every seller controls directly, while repairs uncovered along the way, an old electrical panel or a leaking basement window, are the part that can stretch the timeline unpredictably.
Anything a buyer's future home inspection, typically $400 to $600, would flag is worth addressing before listing rather than after an accepted offer, since a surprise found mid-transaction tends to cost more in renegotiation than it would have cost to fix upfront.
Joel Dyck walks a seller through what genuinely needs fixing before listing versus what can simply be disclosed. Get your hand-reviewed valuation from Joel Dyck.