Is there any rule to be followed in converting dumb solid to parametric? also whether the dress up feature like corner should be followed only after the surface is built?

In general, I try to follow this path when making a model:
1 - Add material to the part
2 - subtract material from the part
3 - Create fine details (i.e. text, logos etc...)
4 - Apply cosmetic fillets and chamfers

Often there are times when the "rules can't be followed. For example, if I am making a hollow or shelled part, I'd likely create some major fillets before shelling the part.

You'll also want to make sure that your dimensioning method makes sense. There is little value in a parametric part if a simple dimension change early in the design ends up destroying later features.

Thank you, if you have any tutorial or guide for systematic approach of the above method, let me know. ;)

Hi,
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https://www.udemy.com/catia-v5-parametric-design/

It's comprehensive course with multiple examples so if you are interested just give it a try.