How can i decrease my refractory period?

Hey forum once again, its been a long time since i was last active here, been through stuff, had some problems, but ive managed to overcome many of them.
Ive come to the conclusion that confidence and experience is what perhaps, we need the most when experiencing certain sexual issues.
After asking all those questions here, experiencing stuff for the first time, ive got an issue which is by much more lighter than those before.
The thing is, when im having sex, the first round goes about 8-15 mins, and its all fine, the erection is great, kept through the whole time, ejaculation is also fine.
When it comes to the second round, usually after 30 mins or one hour, i somehow have to force myself to have sex again, and if i manage to get an erection and put on protection, i somehow fail to manage the erection or ejaculate at the end.Ive read that theres a thing thats called refractory period.
I wish to decrease it, lower the time between rounds of sex.
I read that i should work out, smoke less etc., but i work out for the last 5 years, never smoke, small amounts of alcohol, in good condition, 22 and still.. Has anyone had this kind of issue and resolved it?