I had asked my sister (@mani_candi_bye) to design a simple pictorial that our readers could easily duplicate and the first one she sent was this cute white daisies pictorial. She did mentioned, you could either just dot the yellow center by using a dotting tool or add a small bead and paint them yellow.
Dotting nail tools
A DIY dotting tool
Pearl beads - they do come in different sizes.
All these items (minus the DIY) could be ordered online or by visiting a nail beauty shop.