The 24-year-old Warwickshire right-hander has been in and out of the team since making his debut against the West Indies two years ago.
But a change of approach and some good form in the preceding one-day series against Sri Lanka helped get him back on track.
"After the one-day series I just felt I was getting into a touch of form," Bell, who made 119 Saturday, explained after stumps on the second day of the second Test here at Headingley.
"I just tried to work on being positive, believing in my own ability and showing the bowler you mean business."
Bell was left out of the three-Test series against Sri Lanka and only regarded himself as a stand-in for all-rounder Andrew Flintoff in the first Test against Pakistan at Lord's where he made 100 not out.
But the all-rounder's ongoing absence with an ankle injury meant Bell retained his place at No 6.
And he then scored 106 not out in England's innings and 120-run second Test win at Old Trafford, albeit, as has been the case all series, against an attack missing injured quicks Shoaib Akhtar, Mohammad Asif and Rana Naved.
"Obviously, having Shoaib lead your attack makes a helluva difference.
"But I still rate this as a good side. At times they've bowled well," added Bell, the first England batsman since Allan Lamb against the West Indies in 1984 to score hundreds in three consecutive Tests in the same home series.
Having previously been a top order batsman, Bell said he was comfortable with his new role.
"I'm enjoying it at the minute. I probably would like to get up the order a little bit but if I have to bat at six and play for England that way then by all means. I want to play for England whatever the position."
England want Flintoff, the hero of last year's 2-1 Ashes series triumph, to captain them for the return campaign in Australia starting in November.
If he does get fit, someone will have to drop out again. But Bell insisted the fear of losing his place was not a motivating factor.
"The motivation for me was not playing against Sri Lanka. When I came in, it was only going to be for one Test match. I've only thought about one Test at a time, I haven't thought about Fred (Flintoff) coming back, I haven't thought about missing out or the Ashes.
"Every opportunity I get, I've just tried to treat it as if it was my last. When Fred comes back one of us will have to miss out but the great thing is that we're showing strength in depth and when Fred comes back it will only be a good thing."
Pakistan, 1-0 down in the four-match series, closed on 202 for two, 313 behind England's first innings 515.
Younis Khan was 64 not out and Mohammad Yousuf, who made a double century at Lord's, 91 not out.
"Younis Khan and Mohammad Yousuf have played really well," said an admiring Bell. "It seemed the wicket flattened out a little bit.
"On this wicket the harder the ball the more it's going to do. As soon as it loses that hardness it's a pretty excellent wicket to bat on,
"The new ball is going to be crucial when we get to it," he added.
Meanwhile Yousuf said Pakistan still had plenty of work to come away with a draw and head to the fourth Test at The Oval starting on August 17 with a chance of squarimg the series.
"It has become a very flat pitch. Younis and I will try to play hard cricket. If we bat two sessions tomorrow (Sunday), hopefully we'll save the game."