People get themselves into trouble with young or green horses when they expect the horse to be able to do whatever they had in mind at that moment. A young horse may often struggle to stand still for long periods of time, especially at the beginning of a session. Bringing the horse in fresh from the field with the idea it should stand still while you groom sets the horse up to fail and teaches it to fight or struggle instead of calmly stand. It’s important to be flexible with them.
With a green horse, if they come in with lots of energy, I often go right to lunging work or groundwork. When they’re calm and still, that’s when I work on grooming, teaching to tie, fly spray, etc. Who cares if your horse is a little dirty in your session. It’s not about getting it done today, but setting them up for a lifetime of success. Once they are comfortable with the individual pieces, you can ask more of them. You’re not losing anything by letting your horse win, because when they aren’t afraid and learn what to do in each situation at a rate they can absorb, you both win.