I'm not an expert by any means but while they are on the roost I start off with some soft yelps just to get their attention. Once it sounds like they turned my way I shut up till after they fly down. Once down I'll throw some purrs. Most of the birds I've taken first thing in the morning was cause I called the hen in and the tom followed. I seem to have better luck mid day by going to several areas and wearing out the boot leather. I try to locate with a crow call but if nothing answers I throw a few loud yelps out then wait 15 min or so. If I don't see one or I get no response I'm off to the next area. Most of the time out on public here once I locate one and get their attention I'll try not to call too much so that he has to seach me out.