Been a long time since I spent any serious time with one, but as I recall SHARP is the key. Also you don't want to force or fight the saw at all. Smooth strokes and a sharp saw will cut amazingly fast.
Good axe to help deal with limbs and pinched blades is also key.
Used to know more than that, it it's been too long!
Oh man...the joys of crosscut! Ive spent to many hours to count on them after 9 years guiding in wilderness areas. . A good pair using a crosscut can make it Sing and its really not Physically hard if you are in rhythm with each other. Big thing is DO NOT PUSH. Using a 2 man crosscut if you start pushing you cause a bend in the saw and it creates friction. Its a pull pull relationship. And yes, a SHARP crosscut will make life incredibly easier than a old dull one. But crosscuts are not easy to sharpen just on your own. It takes special tools to set the rakers to certain degrees and sharpen etc...We used to send our saws to the one guy in the area who knew how to do it after each season. He would set some better for trail clearing, and others more for bucking up wood for camp etc. Having a couple axes and maybe a wedge will be beneficial into not getting the saw in a bind. Its definitely an art, but its not rocket science. just lots of sweat and some cuss words! Also depends on what type of crosscut you use. We mainly used 6 foot M tooth 2 mans, but you can also get 4 foot single/double that are easier to pack and can have an extra handle to make it a 2 man saw. The 6 footers obviously cant be run alone and work much better at getting work done
I'd rather use a crosscut than a chainsaw any day. It might take longer, but I find it more satisfying. I've got a 6' felling saw and a 6' bucking saw for work. We also have a 6' bucking saw that broke in half and can be used in two 3' sections by one person.