We need a bit more info first.
When you try to start it does it get hard to pull?
If you try to start it several times and then remove the glow plug and give it a few pulls, does fuel come out the top of the engine?
How old is your fuel, have you used this type of fuel in the car before?
What type of glow plug do you have in the car?
have you checked for air leaks in the exhaust and carburetor and lines?
Are there bubbles in your fuel line?
Is your air filter clean?
Is your exhaust blocked off?
Let us know as much as you can and I'm sure someone will figure it out