How do I get accurate DNA results?

Although he is dead, I would like to go for a DNA test to confirm whether he was my father. I have step brothers and sisters. How do I go about it? Vanguard 

Dear Vanguard,
In the past, resemblance was used to determine who one’s father was. This was erroneous since people who are not even relatives may resemble. Afterwards blood groups were used to rule out rather than determine parenthood. Even this was not very helpful, the reason why DNA testing, which is more accurate has recently come in handy.

In your case, since your father is not alive, step brothers and step sisters together with their mother’s DNA profiles can be made and you and your mothers DNA profiles made and compared to get the paternity. The problem might be if all the step children do not belong to your assumed father.
In case the mothers are not available, then DNA profiles of the boys can be made and compared with your own DNA profile and pray that your step brothers belong to your assumed father.