what are the problems you get because of smoking

I am planning to quit smoking from last 10 years but could not do that. I tried different methods to quit smoking like

1) Reducing the number of cigarettes
2) Tried a bit to smoke low nicotine cigarettes.
3) Tried pathes- for which i had to spend lot of money.
4) Nicotine chewing gums.

I tried all the things but could not succeed.
I am feeling bad because my health is getting deterioated and dont have stamina what i used to have 10 years back.

I am getting some breathing problems because of it.

I need to find out any other ways i can quit smoking.
If any one has any suggestions it will be great help.