If the IAF is on a radial, do a point to point navex to join the radial outside the IAF distance (so you cross it at less than 30°, of course).
If the IAF is on an arc (and no, reynolds1, there aren't inifinite IAFs on an arc), join the defining radial outside the arc short of the IAF, then join the arc and fly around it to fly thru the IAF.
If you are not comfortable with the above, track straight to the fix and do a sector entry, which of course will require some type of point to point nav if the holding pattern is not overhead an aid!
