He's made changes to his technique and physique since the Commonwealth Games.
"I was disappointed after Glasgow but knuckled down with Kirsten [coach Hellier] and believe I've learned what I was doing wrong," Gill said from New Zealand's build-up camp in Japan.
"[My feet] had a really wide base and I was taking a long time to get off the back [of the circle]. I've narrowed my base to increase speed so I can turn faster. It's changed the whole look of the throw.
"I was putting on weight [Gill peaked at 122kg] and, while I was strong physically, I realised I needed to get my explosive power back. I lost about 8kg one month after the Commonwealth Games and I started throwing further.
"I want to look and feel like an athlete. I want to be able to jump over high hurdles and run at a reasonable pace. I don't want to be a big person who can lift heavy weights but can't jump because I'm worried my knees might give out. It's probably better for my health, too.
"I was trying to look or be like other throwers, but I learnt I should just keep trying to do my own thing."
That "own thing" is evident in Gill's latest video release. He is Mr Ballistic. There is footage of his running speed via head cam, swinging a sledgehammer into tyres like he's auditioning as an extra in Braveheart, and hammering a boxing sparring partner with a blur of punches. In addition, he set new personal bests with various lifts.
Perhaps most importantly, it looks like training remains fun.
Retaining a spark of enjoyment is crucial for an athlete who was so dominant as a youngster.
Gill is hoping to make the final 12 at the world championships but acknowledges his event has advanced into a competitive new era.
Gill set his personal best of 20.75m to win the Australian national championships at Brisbane in March. That would have earned seventh at the 2013 world championships in Moscow. This year 19 athletes, including New Zealand's Tom Walsh with a best of 21.50m, have already thrown beyond Gill's mark; 17 did it across 2013 and 21 in 2014.
"I probably should be looking at distance [as a benchmark] but, to be honest, I'm thinking about my place. If I get to the final at the age of 20, it would make all the training worthwhile.
"I haven't been challenged in that forum before. The Commonwealth Games were a test but this field is a lot stronger. I'm looking forward to trying to handle that and dealing with the nerves."
Gill hopes a strong performance would also draw Diamond League invitations next year as preparation for the Olympics. If he makes the Beijing final, he will earn a minimum performance enhancement grant of $30,000 from High Performance Sport New Zealand.
"Next year one of my goals is to compete at two to three Diamond Leagues and make some money, so I'm not relying on my parents so much," he quipped.
NZ world champs team
Men
1500m & 5000m: Nick Willis
400m hurdles: Michael Cochrane
Shot put: Tom Walsh, Jacko Gill
Javelin: Stuart Farquhar
20km & 50km walk: Quentin Rew
Women
800m: Angie Petty
1500m & 5000m: Nikki Hamblin
3000m steeplechase: Rosa Flanagan
Discus: Siositina Hakeai
Heptathlon: Portia Bing
20km walk: Alana Barber
