First IUI this month. Feedback appreciated

So we are trying IUI for the first time this month. Last month we doubled up on clomid and I had a HSG. All looked good but unfortunately didn’t get pregnant. At first the dr had mentioned doing an ultrasound before doing it and now they aren’t. Also what is a trigger shot exactly and does it help? I have regular cycles and I get positive opks every month at about the same time. I just want us to have the best chance for this to work. Any feedback is appreciated. I take prenatal pills and folic acid as well already.