Focus on what I don't want?
What??? I can hear you thinking ;) ....
Yes you should! and here's why :)
Ok so perhaps the title is a tad misleading ;) ... but not entirely untrue. I'll explain
Often people are unaware of what they truly want. When they think of an ideal partner for a relationship for example they may have vague general statements about what they want. He/she should be nice - well DUH! ;) ask this same person to define "nice" and they may struggle a bit putting into words exactly what they mean. If you can't express it then you certainly aren't going to be able to efficiently manifest it.
For this example, to get a very clear and precise idea of what you DO want you need to spend some time focusing on what you don't want - perhaps what you experienced in past relationships that was negative.
Take a sheet of paper and on one side (this doesn't have to be for relationships it can be for an ideal job, or whatever goal you want) Anyway, on the left put "Don't want" or "Won't work for me" etc. and make a list of these things. On the right side of your page create a "clarity" or "manifest this" column and focus on the true opposite of what you don't want.
Don't be vague either "Mean" and "Nice" are not good comparison contrasts ;) A good example might be on the "Don't want" side to put someone who speaks to me disrespectfully and on the "clarity" side - "someone who is wise and respectful enough to show restraint before speaking - who can speak with true honesty and candor without being insulting or rude" This is a very clear idea of what you truly want - not just some vague generalizations.
Remember the key to manifesting is to understand thoroughly, in painstaking detail, what you want to create. Sometimes the key to doing that IS considering what you don't want! - but only as long as it takes to help you determine what you do!
Blessings and Light