Hewett's first season at the helm of the Stags came to an end on Sunday with a 38-26 loss to Manawatu.
The loss meant the Southland team finished its 2018 Mitre 10 Cup campaign winless.
Hewett's under-20 role, as well as business and family interests, meant he was unable to spend a lot of time in Southland before this year's Mitre 10 Cup.
The majority of the workload was left to assistant coach Jason Kawau, with fellow assistant coach Dale MacLeod also not joining the organisation until April.
Hewett's limited time in Southland was a situation which created angst among some in the Southland rugby community.
The former All Black prop said he had already committed to the New Zealand under-20s job before being appointed Stags coach in late December last year.
He also made the Rugby Southland board aware of other interests he was committed to, he said.
Hewett expected next year's preparation would be much smoother, given he was already in place and he would not have the New Zealand under-20s commitment to factor in.
He also had a better understanding of Southland rugby and the challenges.
He said fitness and skill levels needed to be lifted during the off-season to ensure the Stags would be better in 2019.
''We need to work with the clubs, and also the players themselves, to lift the level of club rugby. But we need the support of everyone to make that happen,'' he said.
Team and individual player season reviews have taken place this week as the focus switched to building a team for next season.
Smart retention and recruitment during the off-season would be important for the Stags.
Hewett said 13 players from this year's squad already had existing multi-year contracts carrying over to next season.
Promising lock Manaaki Selby-Rickit lifted that number to 14 last week when it was announced he had also extended his time with the Stags.
Others would probably need to stamp their claim for a contract next season through club rugby.
Hewett believed that in a lot of positions Southland had the players to be competitive at Mitre 10 Cup level.
However, he acknowledged there would be areas which needed bolstering from outside the province.
Loose forward Tony Lamborn provided the Southland pack with some experience this year, but it was unlikely he would return for a second season with the Stags next year.
Instead, Lamborn would likely line up for the United States at the World Cup in Japan.
It is understood there had been discussions with former Highlanders flanker John Hardie about the prospect of returning to New Zealand to line up for the Stags this year.
That never eventuated, but the prospect remains on the radar.
Stags centurion Josh Bekhuis was another player tipped to possibly return to Southland this year, but instead the lock landed a deal in Japan.