Check that you have the correct tools and materials to carry out your intended repair. Apart from the usual spanners, screwdrivers and sockets, hexagon and `Torx’ (star) drive fasteners are now in common use.
If possible wash the repair area with a good detergent or a washing soda solution to remove any traces of wax or silicone polishes/trim dressings. Silicone products in particular will have serious effects at most stages of the repair, some immediately obvious such as masking tape not sticking and silicone spotting in paintwork, others long term such as poor adhesion of fillers, primer and paint.
Remove mouldings and other body fittings such as lamps, mirrors and bumpers if they are in danger of being accidentally caught during sanding or painting. This makes sanding, etc. much easier and also removes the risk of leaving paint edges on or around the item concerned. Some degree of discretion should be used in deciding which parts to remove, i.e., if it will become a major dismantling task simply to remove a headlamp which could reasonably be protected with a few layers of masking tape, then many hours of work can be saved by masking and careful sanding.
Obviously all different makes and models of cars use varying methods and locations for fixing bolts or screws for lights, bumpers etc., but with a little examination of the items concerned most mainstream models can be dismantled without too much trouble, rusted and hidden fastenings notwithstanding.
Body side mouldings can be fastened by either press-on clips, nuts and screws from the inside of the panel, double-sided adhesive tape, or occasionally a combination of these.
Glass and windscreen mouldings are best left in place unless the operator has experience in their removal.
Try not to get carried away and remove too many parts! and if in doubt about anything, either don’t do it or get professional advice.
How to repair dents in car bodywork