I did some relief breeding for Select Sires tech for several years. He taught me, then about a year or two later I took the SS AI class. 2 days working on stockyard cull cows after a couple of repo tracts from slaughtered cows; put in a plastic bag so you couldn't see anything. Interesting but still was helpful. It is true some people never get the feel for it, but most can get a fair amount of success .
It is real important to be able to do cows that are in full heat as it is so much easier to get the rod in. I personally much prefer cows than heifers. I find the cervix in a heifer to be soo tiny and thin; but I started out on dairy cows so they were already stretched out some. I still often close my eyes while "seeing" the cervix in my mind and my son has teased me about it. But whatever works. And yes, sometimes it helps to get the cow/heifer in and put a bar behind and not catch the head so they don't fight as much, but I find that the biggest thing I fight, is one that will crowd over to the side so I am having trouble getting it in straight and being able to feel at the same time.
I only breed on natural heats, we have a 90 day calving window for most because of putting them out to pasture with bulls and not always being able to get the bulls out to keep a 60 day window. But if the cows are in good condition, we find most calves come in a 6-8 week time period.
I watch the ones I want to AI for a month to catch heats, and have given them a shot of Lut to get their cycles closer on occasion, but not too often. I allow them 2 AI breedings, then they go with a bull in most cases.
You can find used tanks at auctions, like dairy dispersals, and sometimes an AI rep will know of one for sale. Haven't priced a new one lately. A breeding box with a rod, sheaths, a thermos and thermometer for the hot water bath, gloves for you, and then the tank and semen. The biggest expense after that is periodic nitrogen recharges for the tank and semen of your choosing.
Agree on getting someone knowledgeable to help talk you through the first few attempts too.