Help! I may lose it.

[Major Rant]

What is most common mistake a hobby spanner monkey like me gets wrong? [img alt=:'(]http://foc-u.co.uk/Smileys/efocicon/cry.gif[/img]

They don't go through the logical fault-finding steps that help to identify problems.  :rollin 

The simple ones are:
Does it turn over?
Is there compression?
Is there fuel?
Is there air?
Does it spark?
Are the plug leads on the right plugs?

Then theres :
Is it sparking at the right time?
Is the fuel very old?
Does it fire at all ?

If there's good fuel, air and its sparking at the right time then its got to at least attempt to run, surely!