Always choose the neighbour who's the smallest, when left with no neighbours go back to the previous country and follow with the neighbour that is second smallest.
Start with the smallest country.
Overseas borders are considered: UK-Spain, Spain-Morocco, France-Netherlands, France-Brazil/Suriname.
Dubious borders: India-Sri Lanka, Malaysia-Singapore and Denmark-Sweden border are considered, Qatar-UAE isn't
A few corrections: Saudi Arabia after Kuwait (Kuwait doesn't have a land border with Iran), Russia after Turkey (since you have to come back to Georgia first) and North Korea after PNG.
I don't understand why Turkmenistan comes after Romania. The last country to still have borders is Russia, but Russia does not have a border with Turkmenistan.