Proper iron temperature: it happens differently if the soldering iron be put on the rosin with different temperature. In general, when we see the rosin melting faster but without smoking, it is the very proper iron temperature.
Proper soldering time: From heating the solder to the solder melting and flowing over the joint, it should be finished within a few seconds. If the soldering time is too long, it’s useless because the solder flux is completely volatilized.
If soldering time is too short, it can’t get enough temperature for pcb board assembly, will cause dry joint easily as the solder didn’t melt enough.
So we must use the right amount of solder and flux, too much or too less solder/flux will affect the quality a lot.

To prevent any flow of solder on the joint, the ideal way is that only make the solder on the right area. In operation, start with less solder firstly, make a supplement when we get the right temperature and the solder begin to cover the joint, then complete in a second.
Do not touch the soldering joint during the whole circuit board assembly process. Don’t move the components and cable on the joint when the solder not solidify, otherwise the solder joint will be out of shape and cause dry joint.
Don’t burn the components and cables with heat iron, pay close attention to the cleaning work after PCB boards assembly finished.
What should we do after soldering:
We need to check the following after soldering:
a. whether there is any missing soldering
b. the lustrousness of the solder joint is good or not
c. the solder on the joint is enough or not
d. if there is any residual flux around the solder joint
e. if any connecting soldering
f. solder pads drop off or not.
g. solder joint cracks or not.
h. solder joints are rugged or not
i. Is there a solder icicles happen or not
S. Pull each components with tweezers, to see whether there is any loose.
A typical solder joint appearance: see below:

Desolering:
Pull the component immediately at a vertical direction when the solder melted.
No matter what the position of the component is like, don’t tug or turn around the components to avoid any circuit or other component damage.
Don’t overexert when pull the components out, don’t turn up the components with the iron.
c. Clean the solder before DIP working, otherwise the pcb pad will turn up easily.