This list a general list that a welder can apply to have the very best weld possible, by far not a complete list but a good one to follow.
*Use only high quality welding machines, electrodes, and welding accessories.
*Know the base material that you are working on.
*Select the proper welding process that gives the highest quality welds for the base material used.
*Select the proper welding procedure that meets the service requirement of the finished weldment.
*Select the correct electrode for the job in question.
*When preheating is specified or required make sure you meet the temperature requirement. In any case, do not weld on material that is below 32 degrees Fahrenheit without preheating first.
*Clean the base metal of all slag, paint, grease, oil, moisture, or any other foreign materials.
*Remove weld slag and thoroughly clean each bead before making the next bead or pass.
*Do not weld over cracks or porous tack welds. Remove defective tack welds before welding.
*Be particularly alert to root fusion on the first pass of fillet and groove welds.
*When groove weld root gaps are excessive, be sure you increase the size of the fillet weld to the size of the root gap to maintain the strength requirement. In some cases, it is advantageous to make a groove weld to avoid extremely large fillet welds.
*Inspect your work after completion and immediately remove and replace any defective weld.
*Observe the size requirement of each weld and make sure that you meet or slightly exceed the specified size.
*Make sure that the finished appearance of the weld is smooth and that overlaps and undercuts have been repaired.