There are 2 types of "ink it up"
1. Is pigment ink and needs embossing powder and heating up.
2. Is a dye based ink that you stamp and leave.
I always prepare my stamps when I buy them. Cover the image with sellotape and press down lift and repeat until you have covered the whole stamp several times. This removes the bits of fluff and the silicone used in the making of the stamp.
I then ink up with the stamp face up using "little kisses"all over the image. Make sure the whole image is well covered. Large stamps are harder to get a clear impression from. I use a pad from my see d stamp pack under the paper or card, if you don't have one of these try using a mouse mat. If all else fails put the paper on top of the image and press down. I have tried all these tips and they all worked well. I only have ink it up and whispers permanent pads and don't have a problem. Hope this works.
P.S store your ink pads lid down so that the ink runs to the surface of the pad