A great way to develop clairvoyance is working with the Ajna Chakra. This is the Chakra between the eyebrow, some call it the third eye but the third eye is actually a thing you obtain by the three head charkra’s resonating together
Using Raja Yoga (meditation with seed) you focus the attention on that spot between the eyebrows. Actually its probably best to use an open eye meditation directly before this, so for instance you could use a white candle, focus your attention on the candle flame for a few minutes then close your eyes and picture the candle again in the Ajna Centre. With practice you should be able to do this fairly easily. Holding the attention like this using Raja Yoga centers the mind makes it still and one pointed. Because you use the mind in Clairvoyance as a mirror or platform for images coming in (spirit use this also to communicate with you) this exercise not only begins to open the Ajna centre but also helps the mind to calm down. You should notice when the Ajna Centre is beginning to respond by natural things occurring, like increased sensitivity via all the senses, seeing more colours like indigo and purples, random thoughts coming in that are not yours. There are many other techniques like this that you can use that we teach in the Inner Circle, at the end of the day it’s about practice and repetition, most people give up if they don’t get results when they want them. Remember anything worth having takes effort.