1) The sprites must be at an exact range from each other, and each sprite must have its own box. Because here, they are at the same distance from each other, but if you put a grid in your sprite sheet, your sprites will not be in the grid. First, you must find the sprite that is the highest, measure its height and find a sprite with the longest width, and measure its width.All that stuff you measured is the height and width of the box in which each sprite will be in.
2) Use Photoshop and cut out the tiles
3) You better use Castlevania 4 sprites
Good Luck.