Change your coils and wash out your tanks. Discard any burnt eliquid.
Prime your coils thoroughly starting with long slow inhales without pressing the fire button (capillary action by sucking is what wicks juice up into the coils, IMO) and proceed slowly in 3--5 watt increments until you reach your desired vape.
Some juices like high Vg and other gunking factors can shorten coil life, chain vaping can also do it, as can the wattage being too high. I guess it's theoretically possible that if you've added VG to avoid throat hit your juice may be having a harder time wicking a few drops (really up to 10% DW if you like but no higher) can help thin the juice without throat hit, instead of PG.
Good luck,
Anna