For my grade 5 I am playing Largo from Winter, Vivaldi. When I play the trills, they are not as clear as I would like and I was wondering if anyone had any tips on how to make them clearer? Thanks

Metronome work can help. Set it at a steady pace, and trill for several seconds at 4 notes per tick, then 6 and 8. Repeat a couple of times before taking the metronome up a notch and doing the same again, and so on. (If you really want to be thorough, do 5s and 7s as well!)

Whatever trills are indicated, however, are probably editorial, so will depend which copy you have. (I'm 90% confident that Vivaldi didn't specify any.) How you perform them, and whether you include them or add others of your own choosing, is integral to performing a piece such as this. Many of them can be slow and calm, or slow and gradually speeding up, rather than all-out rapid hammering.

This is my choice of contrasting performances, both equally excellent in their own right, but achieving quite different effects. The second in particular demonstrates how the soloist can add their own ornamentation as they see fit.

Thank you so much I will try that

Can I just add - remember to trill from the top note in an authentic baroque style. Eg. if the music reads trill on a F , play a G and trill down, not down to an E