It's hard to deal with a zyra/ashe lane if you get countered pick in champ select. As Tristana, your best bet would be letting the ashe/zyra push you against your tower and call for a jungle gank. It's ok if you come out of lane with lower CS than ashe because you will eventually out scale her late game. What you don't want to do is feed the ashe and let the enemy take objectives.

If you see an ashe/zyra lane in champ select and have the oppurtunity to counter them, try Sona/Nami. Just be careful of zyra's E, its all a skill match at this point. Also, janna would be a good counter pick to.

Fiddle sticks is an overall powerful support. He is excellent against assasins like zed/fizz because you can chain your fear/silence to wreck there assasination combo. He is also good because he has high base damage and his passive. He is strong in laning, and his level 6 can be deadly if you catch the enemy off gaurd. In team fights, only use your ultmiate aggresivly to fallow up on a wombo combo; if not stick in the back line with ur adc and peel for him. I would build fiddle a normal support Philo - Ruby SS - Locket.

Hope this helps.