In Islam, what does it mean if one is thinking/speaking of something and then it occurs or they hear about it straight after e.g. thinking about a place and someone else brings it up, or thinking/speaking about someone and then you see them?
Islam is not an encyclopedia of knowledge from which answer to any question could be provided. Islam is a set of beliefs, laws and moral directives that help human being purify himself in order to become a better servant of his Lord and to reach success in the hereafter.
Your question starts by: "in Islam, what does it mean if one is thinking/speaking of something and then it occurs"
This is based on the assumption that Islam, as a religion, explains all the knowledge that is known and unknown to human being. The assumption is not valid, therefore the question cannot be answered.
All I can say is that the situation you described, that usually happens quite a lot for many individuals, is a further proof that us, human being, have only little knowledge of creation of God and that there are many things that (at least for now) we have no clue about them.
As the Qur'an says:
"... only a little knowledge is given (i.e. made available) to you (i.e. human being)" 17:85
This should further strengthen up our belief in the Almighty and prompt us not to be deceived by the extensive, yet still very tiny knowledge that is captured so far by human being.