"What he has to do is finish the race, more than win it," the 68-year-old triple world champion told Reuters at a signing of his autobiography on Monday.
"He needs to get it into his head that he doesn't need to win the race."
Stirling Moss once called Stewart "the first of the modern-style drivers, a man who drove fast enough to win but at the slowest possible speed" and the Scot advocated a tactical approach to what will be a three-way showdown at Interlagos.
Hamilton, a 22-year-old sensation in his rookie season, leads Spanish team mate and double world champion Fernando Alonso by four points with Ferrari's Kimi Raikkonen a further three behind.
Hamilton needs finish only second to take the title and could even finish far lower than that and still be champion if his rivals slip up.
He might have sealed his place in history already as the first rookie champion, as well as the youngest, at the previous race in China but skidded out on worn tyres while entering the pit lane for his second stop.
"It's a great temptation for a young driver, particularly as good as Lewis is, to say 'No, I'm going to go out and win the race,'" said Stewart.
"Had he taken that other view in China...he would be world champion now. So it's not always important just to win.
"It's success that you are after. World championships are about winning but they are also about success and achieving. He's got to get through the first corner, then finish the race. He's got a lot on his plate."
Stewart recalled how he had been in a similar position to Hamilton in 1968, his fourth season in Formula One, when compatriot Graham Hill led a three-way battle to the final race in Mexico.
"Three of us went into it capable of winning the championship -- Graham Hill, Denny Hulme and myself. Denny after 10 laps had a suspension failure and I had a fuel pump failure," he said.
"Graham won it and won it well. In fact it was almost better that he did win it, because I'm not sure that I was ready and prepared to be the world champion and be able to carry it out in the best possible way.
"I can say that now, but I didn't feel that at the time. The disappointment was colossal."
Stewart said he had no fear of Hamilton, who he felt was better prepared than any of Britain's recent champions or the likes of Ayrton Senna and Alain Prost, being unready.
"Lewis Hamilton is capable of winning the world championship, no doubt, and he's the best young driver I have ever seen enter the sport," said Stewart.
"But the preparation for Brazil is something that nobody could actually coach him on, without having a long programme of preparation.
"At the end of the day it will be down to his own intellect to deal with in the most appropriate fashion."
