>1. Keep Good Mentality: because once you are frustrated , you may not be able to solve any problems.
2. Know Feeding Processes: Let's take broden extruder as an example: Filament tray - Extruder - Teflon tube - Hotend - Throat pipe/ heat break - Nozzle, these could help us shooting the problem quickly.
3. Basic Setting: Extruder motor and slicing parameters, if you don't know how to set then please use the default parameters.
4. Filament: check if there are phenomena, impurities, damp, dusty or large diameter error.
5. Extruder: The gear is slippery or too tight, recommended to lubricate it or replace it.
6. Teflon Tube: check if the inner wall is smooth and resistant to high temperature.
7. Pneumatic Head: it is recommended to use straight through type, or pay attention to the connection during installation.
8. Throat Tube/ Head-break: If the cooling effect is poor, it melts in advance, or is blocked during the extraction process.
9. Hotend Fan: check if it is installed backwards or broken, and the cooling effect is poor, causing the filament to melt in advance.
10. Nozzle: check if it is not tightened, or residual filament blocked, and the installation is crooked.
11. Nozzle Fan: Adjust the direction, do not blow on the nozzle, because low temperature is unable to fully melt the filament and cause blockage.

Although most of blocking caused by the throat/ heatbreak, not all of them are. Before you replace it, please shoot issues according above steps.