Advice on bubble study

I am a new grad in the field, and I work the weekend shift at my hospital, usually working by myself or with one other tech who is either portable all day or on outpatient all day, which means i am independent for most if not all of my shift. How do seasoned cardiac techs perform bubble studies? Do you always ask someone on the floor like an RN? I have tried doing it myself only a couple of times and keep missing the window to see the bubbles, is there any tips or tricks to effectively perform one by myself? I also understand it requires practice too but I would love some tips to get better :)❤️