Rule one: don't use plastic glue. It'll break after a while, fall apart, and fuck up your paint job. Which I don't have to tell you... sucks. You have to use super-glue.
Rule two: pin the joints. If you don't know what this means, it basically entails drilling a hole on either side of the joint and putting a small piece of wire in there. When you glue it together after doing that, the hold is about a million times stronger (give or take a few factors of magnitude
).
Rule three: if the model is particularly top heavy, weigh down the base if you can. I glue some pennies to the bottom sometimes, but on the 40mm base, you can't really do that... I dunno. Get creative I guess.
I suppose that's all I'd say for metal assembly... Count yourself lucky at least. It used to be that
all the fuckers were metal, and what tiny oases of plastic there were sucked ass like you wouldn't beleive. Those old plastics are the worst models GW has ever put out, no joke. Well, except the old Genestealers. But everything else sucked.
Plus, can you imagine putting together a, say, 200 model Imperial Guard army, every model a pewter model? No thanks...
Other than that, practice, practice, practice. Believe me, it does get a lot easier. And if you can, start with crappier models so you can get used to the process, that way your showpieces really look their best.
Good luck man. I'm glad to hear your progress is so brisk!
(As for me, my local store is getting Warhammer in soon — like a few weeks/couple months soon. I can't fucking wait.
)