lewis structure

[Primarygun]

About the drawing the lewis structure, I am puzzled with deciding whether using the dative covalent bond or the double bond.

What are you guys' very first step in drawing the structure of the covalent molecules?

May somebody draw the structure of chlorate ion and sulphite ion?

Is the biggest, most important task in drawing lewis structure is to give the every atom an octet structure and this task cannot be achieved only when there's a noble gas atom,right?

and for the structure of sulphur dioxide molecule,

if there is one dative bond and one double bond instead of two double bonds, then sulphur atom can obtain ocetet structure, but in reality, why this is not the case?