one thing i've found that works well with infi is to increase your angle on the edge for the final polish.

If you make the final polish slightly more obtuse than the original edge angle, you'll be able to get a shaving sharp edge...

for some reason, i find that if i try to keep the exact same angle all the way through, i get a micro-burr along the edge

you can also fix this by stropping after you finish your 3000 grit polish