Please keep in mind there will always be a degree of "Chemistry" involved but this guide will explain some actions you could take to "Mix the chemicals up" a bit.
WARNING: I will do my best to keep this PG-13 but it will contain some sexual references.
Please also note that this is a no B.S. tutorial. Some of this will come off a bit sexist and entirly what you can do for him to encourage attraction.
Step 1: Minimum System Requirments
to keep this tutorial to a reasonable length and within the PG-13 standard, I will recommend you keep within plus 2 your league or below.