Hmmmm.. simple answer is this: It's a Gurkha.
No trick, if you want to keep smoking them, reach for your lighter and touch up when you need. When I need to really fix a burn, I scrape all the grey ash off that I can (as you do this, you will see the area that is not burning properly), then relight the whole thing. If you don't get rid of the grey ash before relighting, you will turn the loose ash into a tar-filled mess that will ruin the whole smoke.
If you get a bitter taste after relighting, purge the cigar (blow through the head for ten seconds, take a break, repeat) and wait a good five seconds before trying again. You will be rewarded with a new cigar after doing all of this crap, which does work, but is a lot of freaking effort. It is the method I use to great effect, but others may have a different way.
Easier to get a cigar that isn't a headache that needs constant life support.