i  thought i had a tutorial on doing inlays on here 

 don’t see it now .
  What I do is use chisels  and gouges to inlay .
. I place the inlay where I want it and then carefully, using a very fine pencil , outline it.
 Then using a small chisel , I plunge down  just inside the lines  that I have traced . This spreads the wood . Come back and carefully remove wood from inside that plunged line so that the inlay sets  down in the wood .
 To hold it in place , you can glue it in . but when I do that I  eather raise small burrs or scribe lines on the back of the inlay so that the glue has something to grip to.
  Most time however I use  counter sunk pins  and nail the inlay in place .
 I then wet the wood around the inlay . This swells the wood  back up tight against the inlay  . If you have  traced the part tightly , did not remove any wood outside that line . The wood will swell back up  very tight  and leave no gaps ..
 Once finished ,  use a file and sand paper to  level and polish the surface