Most hiring pain starts before the first posting goes live, in the gap where a plan should have been. The plan does not need to be elaborate. An afternoon and a shared document will do, and it buys back the two weeks you would otherwise lose in month three.
Size it against work that is already blocked
List the work you cannot deliver with the team you have now. Then turn that list into roles rather than wishes. The test is blunt: if a role does not map to work that is already blocked, it is not this quarter's hire, however much you would like it to be.
This sounds obvious and hardly anyone does it. Most headcount plans are assembled from what each manager asked for, which is a different document with a different purpose, and it tends to add up to more people than the work justifies.
Sequence it so the early hires help you
Hire the roles that unblock other roles first. A team lead who starts in month one makes three hires in month three far easier, because somebody other than you is running their onboarding and reviewing their work.
Getting this backwards is how a team hires four people in a quarter and comes out of it slower than it went in. Everyone is onboarding, nobody is shipping, and the person who was already stretched is now training four people.
Budget the whole thing, not just the salary
The compensation band is the part everybody remembers. The rest of it is recruiting spend or placement fees, tooling and licenses for the new starter, and the internal hours your interview loop will eat. Four engineers spending five hours each on a loop is most of a working week taken out of the roadmap, and it almost never shows up as a budget line.
Agree the compensation band at this point rather than later. Setting it before you post is what stops an approved offer collapsing at the final step, and it is much harder to argue about in the abstract than it is with a candidate waiting.
Decide the channels before you need them
Some roles have a healthy applicant market and a direct posting will fill them. Some will not, and you usually know which is which before you start, because they are the roles you have struggled to fill before.
Sort them now. The reason to do it early is not efficiency. It is that the alternative is a decision made in week six, when the role has been open long enough to hurt, the team is covering the gap, and you sign whichever contract is in front of you.
None of this survives the quarter intact, and that is fine. A plan you have to revise is still worth considerably more than the four separate assumptions everyone would otherwise be working from.