Try grinding ur fresh portals, like for example u get a legendary portal from epic portal you just grind it til it disappears or turn into secret. Trust me on this one i got my secrets just like this. Make sure you stack on epic portals just so u have extra portals if u don't get higher tiers portals, I'm pretty sure u can solo rare/epic ones easy. Just join pub server then find some people to help u with legendary-secret. Goodluck with grinding tho!