Yes there is a way. But first let me clarify something...
There is an upper and a lower boundary of where Tefillin may be placed. Anywhere between these two spots is fine. The area is rather large, to the extent that Chazal say that there is enough room on the head to put two pairs of Tefillin at once. (Indeed some sefardim and others weare Rashi and Rabbeinu Tam at the same time.)
Based on this, the best, surefire way to make sure your tefillin are placed properly is to find the upper boundary and put them slightly below it.
The good news is that the upper boundary can be pretty easily located on most people. It is a subtle dip around the middle of the top of your head, called the 'coronal suture'. If you feel along the top of your head, you should be able to find this dip.
Once you have located it, make sure that your tefillin are placed slightly below it, and you are guaranteed that your Tefillin are within the permitted zone (Unless your tefillin are gigantic).