"I've never been much of an optimist; I'm a realist and I'm realistic in knowing what I have to do and I'm confident in knowing that I can achieve that," the South African told reporters on Tuesday.
"In athletics it is not about working hard and achieving a goal, it's about working hard every single day and we've still got 122 days until the Games and every day has been planned and calculated."
Pistorius, who uses carbon fibre prosthetic running blades, ran a 45.20-second 400 metre race on March 17 in South Africa to dip under the qualification time of 45.30. However, he still needs to run the qualifying time in an international meeting before he will be considered for South Africa's Olympic team.
Last year, Pistorius became the first amputee to compete at the athletics world championships when he ran in Daegu, South Korea, though he failed to qualify for the 400 final.
If he qualifies for London, he would be the first amputee athlete to compete at the Olympics.
"It's nice being able to run the times, or close to the times, that you need for the 400m now but there is a long season ahead of us still," he said.
"Hopefully I will start the European season off with the same confidence that I have now, and between now and then get some proper training done."
The 25-year-old Pistorius, who has a best 400m time of 45.07, is competing in the National Championships for the Physically Disabled in the coastal city of Durban and said running in the hot and humid conditions at sea level had been a worthwhile exercise.
"We used this week as a good training week and running in air this dense is a challenge but you get the same challenges when you are in Europe," he said.
His coach Ampie Louw said Pistorius was in fine form ahead of his European season which starts on May 25 in Ostrava in the Czech Republic.
"He is in good shape. We are only starting with our real speed work next week.
"I think that a 4x400 relay qualification is a certainty but his personal goal is to make the final (in the 400m) at the Olympic Games," said Louw.