Hola
If you want to say "I try something"
If it's sports, you can say "わたしは、somethingをやってみる。"
If it's food, you can say "わたしは、somethingをたべてみる。"
If you want to say "I want to try something"
If it's sports, you can say "わたしは、somethingをやってみたい。"
If it's food, you can say "わたしは、somethingをたべてみたい。"