I use a bender. Nothing to it really although occasionally a bend is a little wonky. Only "tips" are:
a) Cut a little longer piece than you need, then bend, then cut to size - unless you're so fantastic that a quick measure gives you a bend in EXACTLY the right place, every time. Everyone on this forum is brilliant at this so it's probably just me.😛
b) Bend the pipe slowly and make sure it doesn't slip in the benders. I find if I yank it round quickly then the bend deforms and the outside flattens rather than staying in a rounded shape.
If you're new to 10mm pipe then this might be useful:
Using a 10mm pipe cutter instead of a hacksaw.
If using a 15mm-10mm compression fitting then ensure this it squarely over the end of the pipe and pushed well into the radiator valve (and holding it there) before tightening.
Using my hands and thumbs when making small curves in the pipe.
With 10mm olives tighten joint rather more than hand tight but don't force the joint at all. If you have a small seep then usually some more tightening sorts it out. If you tighten it too much to begin with then you risk deforming the olive too much so it won't be water tight no matter how much you tighten it afterwards.
When fitting 10mm for oil you need an oil sleeve nowdays (to keep OFTEC happy). You'll also find that using a sleeve you can tighten the join much more than normal so be more certain of an oil tight joint before you turn the oil on again.
Hope this post hasn't been too patronising.