In Japanese to say "to want to do something," you have to change the form of the verb which is as follows: example: To go　＝　いく First use the original form of the verb and change く　to 　き just as you would for the ます-form of the verb. Lastly add the suffix -たい to express "want to." So, the phrase "I want to go" is いきたい "I want to go to Japan" = にほんにいきたい The たい form of a verb can easily be remembering how the stem of the verb looks in the ます form and adding たい.

Lee already covered most of it, but I figured I should say, ほしい Is ONLY used when referring to an object.

No. にほん　へ　いきたいです。 Vたいです　 : want to do V