Half moon manicures are super easy (if a bit time consuming) and they definitely get easier with practice.
I've seen a lot of tutorials posted online using sticky tape, or those ring binder things to make the shape - but I promise, you only need two special tools to do a half moon manicure:
I prefer Gel Nailpolish as it's long wearing and my nails are really brittle, and the polish is easier to maneuver (it levels itself). Tasha has a really good Gel Nail series on her blog here, so I won't go over how the nailpolish works or how to apply it. If you've never tried it before, give it a go, but for now I'll assume you've cleaned your nails and set your base coat under the lamp.
Step 1: Apply a thin coat of colour polish starting about 5mm (1/5 of an inch) from the base of your nail - you want to leave the lower part completely blank
Step 2: Make sure your brush isnt too loaded with polish, and carefully do the sides at an angle
If it doesn't look neat, don't worry you can fix it later (i.e. like my index finger here)
Step 3: Get your soft brush and dip it in the acetone. Blot off the excess onto a tissue, and carefully 'push' the ragged edges of the nailpolish with the brush until you get a curved shape you like
Do this for every finger, and set the colour coat under the lamp. (I finish one hand completely before starting the other one).
Step 4: Apply a second colour coat, keeping within the nice curved lines you made. I normally get close to the edge, but not right up to them
Step 5: Set the second coat, do your top coat and cleanse with your alcohol cleanser as per normal. Finished!
I admit it does take a bit longer than applying gel nailpolish the plain way, but it's not very hard either.
Do you do a half moon? What are your tips?
Gel nailpolish - High Roller from Couture Gel
1940s repro jumper - Sweater Girl at My Baby Jo
Diamond ring - Safari Lee
Jewellery and scarf - various
Lipstick - Nars velvet matte pencil in Red Square