How to make my zippo lighter more reliable

I Mine does that But when I light it backwards then frontwards i get a flame

First, use only Zippo or Ronson fuel. other fuels can leave carbon or waxy residues. They also may not ignite reliably.

SECOND, take a Q-Tip soaked in fuel and wipe clean all the sooty deposits in the chimney and around the flint & flint wheel (Best done with the wick OUT). These deposits can prevent the spark from reaching the wick.

AND of course, you can always make use of Zippo is repair services.

GOOD LUCK

if it is a genuine zippo, send it back to the factory, they are guaranteed forever.if it is a knock off, just get another one..you might want to change the wick

Have you replaced the flint too?

http://google.com/products?q=zippo+flints&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7GGIT&um=1