How can a double-digit kyu player study and learn which moves are urgent in the early stages of the game?
If you are not sure whether a local play in the early game is urgent, play elsewhere. Your opponent will have the opportunity to prove you wrong, and if he does, you can learn from that. See When in doubt tenuki. As for study, watch high level games and play over pro games.
For DDK, study of high level or pro games gains more confusion than insight because strong players play elsewhere a lot. Thereby, the DDK does not learn what he needs to learn: the basics of defending weak important connections, groups and boundaries of major territories.
Learning by doing mistakes all the time is the hard way. Not being sure and playing elsewhere causes very many extremely big mistakes. Without guidance, the DDK does not realise the causes of his bad positions. As a teacher of ca. 150 players, I have seen more than enough examples of kyus players playing elsewhere in case of doubt. In circa 99% of the cases, it has led to desaster. Therefore, the advice of playing elsewhere in case of doubt (regardless of its possible use for dan players) belongs to the worst possible advices ever given to DDK.
From the same teaching experience, the successful advice for intermediate kyus and DDK is: Defend your weak important connections, groups and boundaries of major territories. In case of doubt whether something is weak and important, think and find out.
The kyu disease is that of following your opponent around, of not taking sente and playing elsewhere. If playing elsewhere has led to disaster, that is a prime learning opportunity. Taking gote is less likely to cause disaster, but also leads to frittering away the game and then wondering why you lost.
There is not only one kyu disease. Missing defense and being the slave are two of the major diseases. If your weak important connections, groups and boundaries of major territories are defended, then stopping being the slave can be good. If weak important connections, groups and boundaries of major territories are not defended yet, it is correct to defend them immediately. (Advanced players know that defense can often be combined with attack for greater efficiency. DDK first need to learn to defend the weak and important at all.)
First identify what is weak and what is important. Defend your weak important connections, groups and boundaries of major territories.