The 49-year-old Welshman succeeded Tony Pulis last month following a miserable 18-month spell at QPR.
But chief executive Tony Scholes has nonetheless overseen a steady rise in sales after a significant drop on their initial launch.
"We finished the launch period 15 per cent down on last year," said Scholes.
"While being disappointed that we were down at all, to put that into context we had still sold 16,500 season tickets at that point.
"Since we have closed the launch period and have gone back on sale with mid-priced tickets, and appointed Mark Hughes, we have had a good response and have sold a further 1,000 tickets.
"We would normally sell 500 to 600 at the mid-price. So, we have sold a total of 17,500 now and have been very encouraged by the recent increase in season-ticket sales.
"It gives us great reason to be optimistic that once again we are going to be playing to sell-out crowds next season."