This is such an easy simple trick to boost the thickness of side braids. To do this you won't set your extensions like you normally do:
1) Section off a triangle of hair off your middle part.
2) Clip in a single clip weft with the clip parallel to the part created in the sectioned hair.
3) Begin your side braid towards the front and work your way back, incorporating parts of the extension as you move back.
4) As you move back, incorporate hair from the back section into the braid to cover up the extension.
5) Finish and tie off.