Increase your tip weight. However you have to watch your spine at the same time. The heavier the tip the weaker your making the spine. You can increase tip weight by shooting a 125 head....you can also glue in two inserts if u use hit or deep6 or add brass weight inside the shaft
Lighter shaft, I'm over 17% with 50gr inserts and 125gr broadheads with nockturnals and ff sk300 vanes, I go over 19% just switching to Easton microlite nocks....but none of that possible without a lighter shaft. Ditch tail weight, no wraps, switch to Easton microlite nocks, 125gr broadheads is quick way to start. My shafts r speedpro 6.2 gpi, total arrow weight 389gr at 28", I get it all, speed, enough weight, and crazy foc, but the biggest factor to start with IMO is start with the shaft. Stay low to mid 8 gpi on 70 lb set ups and 125's up front, don't get carried away out back. On the hooter shooter out of my specialist 70lb my 6 arrows did a 3/4" group at 20 yrds right out of the gate, twisting a couple nocks brought it to 1/2", the shop was impressed and only saw maybe one setup in for a supertune do an initial group that tight or better before nock tuning, so seems I've stumbled upon a good thing in my arrow building quest. Heavier the shaft the heavier u have to go up front so it's easier to start with lighter shafts to get the flexibility in components and even just to have over 10% with a 100gr head.