At the first hint of a gurgle either hit it with a quick pipe cleaner or gently blow to push the accumulated moisture towards the hot ember
If you build up lots of moisture it may be from exhaling through the pipe too much or from smoking the pipe too hot. It should stay cool enough so that it is not uncomfortable to the touch. Cool enough to hold against you cheek for the most part
Great links mentioned - all I can add is:
1) loose at the bottom of the bowl and tighter on top is crucial and is the drive of all the packing methods. This is because the bowl is a small furnace and will suffocate without the drafts in the bowl caused by the warm loose lower layer - at least that's how I understand it
2) pack to just below rim, false light, tamp back to just below rim, repeat until well lit, then only tamp -very lightly- just to compress the ash, not to compress the tobacco - which would ruin your loose bottom layer - unless you need to tighten it up a bit of course, which is par for the course at the very end, or needed if you packed a bit too loose to begin with
3) always draw while you tamp, you will learn from the change in air resistance how much is too much
4) in the three step method the first packing and tamping will create zero air resistance, with the final third packing providing gentle resistance
5) much easier to keep lit when you mostly sip from the pipe, sipping and breath smoking with the occasional puffs. If mostly puffing you will need good timing to keep lit without overheating -
6) if puffing, about 30 seconds between puffs should work best, with one or two puffs, never three. Some pipes will last for several minutes between puffs if packed well, such as a calabash.