Flippin' thing wont start!!

[Grub123]

Hi All,

i have just acquired an early 1980's XT600, kickstart only. it appears to be an Italian import (i am in UK). it's all there, a bit scruffy (but it is 20+ years old). i can get a spark, it has a new carb on it (so i am told) and lots of compression.
But i cannot get it to fire let alone run. I know that there is a very wide range of things it could be, but i wondered if anyone could help me with where to start?
I also imagine that there is a "knack" to kicking the beast up too. i want to tackle the problem systematically and am keen to hear any ideas as to where i should begin.
i do have some basic engineering knowledge and skills, but as said, there may be a preferred route to solving the problem.

the bike is too good to be left in a dark corner! i need to get it running then i can think about getting it registered for road use in teh UK.
i am unsure of the year, but it has disc front brake and a drum rear, monoshock rear suspension, gold rimmed wheels.

Any help welcome. cheers.