"I have learned a lot since I made my marathon debut in London in 2014," he said to reporters on Tuesday, reports Xinhua news agency.
"I understand the marathon more, so I will go after the British record and see what I'm capable of. My aim on Sunday is to respect the other guys and get on with the race."
Farah, also a multiple world track champion, set an English record of 2:08:21 four years ago, which makes him the 13th fastest in Sunday's field, a line-up containing eight athletes who have run under 2:06, including the second and third fastest men in history in Ethiopia's Kenenisa Bekele and Kenya's Olympic champion Eliud Kipchoge.
"It's a great feeling not being the favourite. There isn't much pressure on me," he said.
Farah retired from the track eight months ago at the London 2017 World Championships and has concentrated his attention on marathon.
"When things are great, that's the time to find a new challenge, something to get you motivated and get you up in the morning. And running the marathon is something I've always wanted to do," he said.
"Having a new challenge has made me feel more relaxed. You have to enjoy what you do, otherwise what's the point? I'm enjoying my running now more than ever."
Farah believes he's capable of clocking 2:04 hours or 2:03 hours "in the right race at the right pace" but admitted that his strategy on Sunday may change if the favourites go all-out in the early stages.
"I will give it 110 per cent, but a lot of things can happen in a marathon and things change quickly, so you never know what will happen. A win would be amazing but I go to every race to fight and try to get onto the podium. It's going to be an incredible race," he concluded.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
