TTC - period tracking & advice?

Hey lovelies, I’ve just come off my period - just wondering when tracking period when officially is the ‘last day’ because I stop bleeding as such after 3 days but for 2 days I get the aftermath of brown discharge so do I mark the last day when that ends or when the proper flow ends? I’m really hoping to get pregnant this month - any advice on increasing my chances would be much appreciated! Have a lovely day everyone 🤍