(2) Is pad design reasonable enough? The pad is too big or too small is not conducive to welding.
(3) Are the packages you designed designed from the perspective of Top View? When designing a package, it is best to design it from the perspective of the Top View. The Top View is the angle when the component pins are seen on their backs. If the design of the package is not based on the Top View angle, after the board is completed, you will most likely have to solder the component in four feet (SMD components can only be soldered in four feet) or to the back of the board (the PTH components are soldered to the back).
(4) Is the relative position of Pin 1 and Pin N correct? If it is wrong, it may be necessary to install the components in reverse, and it is likely that you will have to fly or even scrap the board.
(5) If the mounting holes are required on the package, are the relative positions of the mounting holes of the package correct? Incorrect relative position can not be fixed, especially for some modules with Module. Because there are mounting holes on the module, there must be mounting holes on the board. The relative positions of the two are different. After the board is out, the two cannot be connected well. For the relatively troublesome Module, it is recommended that the ME should first make the Module frame and the mounting hole location and then design the Module package.
(6) Did you mark Pin 1? This facilitates later assembly and commissioning.
(7) Are you designing an outline or a frame for a Component or a Module? This facilitates later assembly and commissioning.
(8) For ICs with a large number of pins, do you mark the 5X and 10X pins? This is conducive to later debugging.
(9) Are the dimensions of various tags and outlines you design reasonable?