Sorry, but I am really, really bad at explaining things! Plus I haven't made any flowers myself in quite a while (don't do many cakes anymore). I use a flowers nail & wxed paper square. Hold the piping bag with the wide end of a petal tip in the center and squeeze while at the same time turning the nail and moving the tip from the center, out, and back. Do this to make 5 evenly spaced roundish petals, then pipe a few dots of yellow in the center.
It just takes practice to get the hang of it and figure out the right angle, speed, etc.
Sorry I can't be more helpful, maybe someone else can explain it better.