I started out their very puppy grooming by gently combing their head hair and starting topknot bows (even when there wasn't enough fur for a knot). I do that on my lap every evening, starting with a few minutes per night and gradually adding time and intensity.
They always get the extra special good girl/good boy grooming treat afterwards (usually a tiny cube of cheese).
I made that nonthreatening, soothing, and relaxing, gradually adding more combing and brushing, and fuller grooming with small grooming sessions on the table until they could handle a full groom standing still. I just gave them both full baths, blowdry, comb-outs and topknots and they were so very good. Shrek is now 6 months old; Sylphide, 21 months old.
One technique I use is to spread out unpleasant stuff. For example, they both hate ear treatment. So, I never do that during any regular grooming. I catch them off guard and do the ears separately. That way, they know not to worry about anything unpleasant while they are on the grooming table. They really don't mind the other stuff.