We actually already have a thread going about face makeup for FtM crossplay:
Basically, it's all in the contouring. You want to put a darker shade under your cheekbones, around your jawline, and by your temples to give your face a more masculine shape. If you want, you can also fake more "realistic" male skin by making your complexion more uneven, as this tends to be the case for boys.
If you could upload pictures of your attempts, I think it would really help so we don't give you repetitive advice of things you've already tried!