Michael Appleton admits he is in the dark on how much progress can be made by his side as Pompey head for the midway point in the season.
The Blues will reach the halfway stage of the campaign when they travel to Leicester on New Year’s Eve.
At the minute, Pompey are three points down on their points tally from the same stage last season.
Despite their horror start to the 2010-11 term, the Blues picked up 30 points from 22 games – compared with this season’s haul of 27.
While previous boss Steve Cotterill had plenty to contend with at the start of last season, with the club still in administration, Appleton’s appointment in November was bound to affect continuity.
And while the new manager puts his plans in place amid new financial uncertainty behind the scenes, he knows he has to be patient with what can be achieved.
He said: ‘It takes time. I’m not daft enough to think things will happen overnight.
‘It’s easy having a vision and a plan – I know that, I’m not stupid.
‘But you are not going to stop me having that vision and plan, and if I get the opportunity to build and do what I want to do, there will be good times ahead.
‘If I don’t, then I can look myself in the mirror and say I gave it my best shot.’
Appleton has already set about changing the style of play and is also keen to freshen up the squad during the January transfer window.
But he also knows his hands could be tied as the club’s current financial situation could scupper any potential deals to bring in new faces.
Appleton said: ‘I think there has already been a vast improvement from the performance at Watford for my first game.
‘At the moment, I don’t know if we will be able to bring players in. But if there is an opportunity to do business in January, we will have the right people in place and be ready.’