I am confused about when to put an ending for a direct object - does it depend on which verb you use?

For example in the homework writing sentences in the future, it´s O.K. to say ´Muzik dinleceðim´,´futbol seyredeceðim´ and ´Kitap okuyacaðým´ but you have to say ´kitaplarýmý deðiþtirmek istiyorum´ .

Please enlighten me someone or refer me to a lesson I have overlooked!

Thank you, Samarkand.

 I think they are should be put into the accusitive.   Muziði futbolu and kýtabý.   but that is just me.   where ýs Melek when we need her?

Here I come to save the day ...

Ok, this is how I understand it (keep in mind I´m a learner too).

In the examples, you´d put a direct object if you´re talking about specific objects. So, I will read a book (any book) would be "Kitap okuyacaðým.", however if you want to say I will read the book (a specific book, a book somebody might have mentioned), you´d use "Kitabý okuyacaðým". You say "kitaplarýmý" and not "kitaplarým" because the books in the example are specific, that is, they are the books that are "my books".

And yes, you have to pay attention to the verb too. Most (I think) verbs take the -i direct object, but for some you would put the noun in a different case (for example with hoþlanmak takes - dan/-den - "Kitaptan hoþlanýyorum" - I like/enjoy the book). The dictionary tells you what case you have to put the noun in.

I hope that helps. 

P.S. There´s a bit about it in this lesson: http://www.turkishclass.com/turkish_lesson_66

Many thanks,

Samarkand