The four things a grader looks at are the four things that decide the price, whether or not the card is ever graded.
What moves the number
Who is on it, and what the market thinks of them this year.
Print run and parallel — the same photograph can exist in a dozen versions at very different scarcities.
Centring, above almost everything else.
Corners, edges and surface.
Raw or graded, which again are two markets.
Why two of the same differ
One was shown still, under side light, front and back. The other was waved past the lens. How cards are graded.
How to find out rather than guess
Compare completed sales matched on parallel and grade. A card's name is not enough — the parallel is often the whole value.
And never price a raw card at a graded number. A predicted grade is an opinion, and an opinion is not a comparable.
Cricket cards in India
A real and growing market with its own scarcities, and one where the specifics matter more than any general rule. Describe the set, the parallel and the condition precisely and let the room price it.
Questions people ask
Is grading worth the cost?
Only when the likely gain beats the fee and the wait, which for most cards it does not.
Does a trimmed card have value?
Far less, and it must be declared. Modern cards have a standard size, so a trimmed card measures short.
What about a bulk box?
Lots. Keep anything notable out of them.
More: pricing sports cards, packing cards.