I am going to make a three tier wedding cake with sunflowers and daisies. I would love suggestions on how to go about this! Need to know how to make sunflowers so they look realistic! Any/all cake suggestions welcome too!

You can buy cutters for daisys that work well for sunflowers too! There are tons of them online, some for very reasonable prices. I'd use a larger one for the sunflowers and a smaller one for the daisys.

Just cut them out of gumpaste or fondant/gumpaste mix. Make a little ball and flatten it into a circle for the centers. I roughed them up with a grass or star tip for some texture.

I used a PME sunflower cutter for large sunflowers and then gerbera daisy cutters in different sizes for smaller sunflowers and daisies. Never done both on the same cake but there is a sunflower cake in my folder that I made entirely from fondant. The centres I made by flattening balls of chocolate paste, brushing them with melted chocolate and dipping them in chocolate vermicelli.
For the daisies I make the centres by brushing the flowerpaste with edible glue and dipping them in either cous cous or semolina, which I coloured using my regular fondant colourings.