[th3byrdm4n]

Second this. Cross functional knowledge is the secret sauce of in-house designed software.

Nothing off the shelf does that.

Integration is where cross departmental solutions live and that’s an underrated nightmare

[Too]

Third this. If the software team (at least the lead) does not know the business requirements, you are not doing in-house development. Otherwise, it is just equivalent to off shore development, that happens to sit in the same building as yourself.

[RaftPeople]

Fourth this.

Other than making sure you find the right person/people from a raw skills+personality/capability perspective, it's the next most critical item.