General Attempts:
* Attempts
* Efforts
* Endeavors
* Experiments
* Trials
* Strides
* Ventures
More Specific:
* Attempts to
* Makes an effort to
* Struggles to
* Seeks to
* Aspires to
* Undertakes
* Tackles
Informal:
* Gives it a shot
* Has a go
* Takes a crack at
* Gives it a whirl
Please provide the sentence you are using the word "tries" in so I can give you the most accurate synonym.