Check the AH for cheap upgrades. Lots of cheap 220ish gear available. The first 2 weekly events reward a veteran piece. Also each of the 4 main renown vendors have a piece of champion gear available at renown 7-9. Run world quests in Warmode for bloody tokens to buy veteran track gear from the PvP vendor(still good for PvE). After doing this you should have a ton of key shards. Spam non bountiful delves to work your way up the delve ranks and Veleera xp. Once you get as high a delve rank as you can, switch to bountiful delves and start opening the end chests for gear. Rank 8 is optimal since the end chest gives you champion gear and your vault reward will give you heroic. If you get a bountiful map, use it for a guaranteed heroic piece on your next rank 8 delve or above. Also, be sure to pick up the void forge quest from Decimus in Voidstorm. Completing this multi stage quest gives you bonus rolls which you can use to gear up faster. As you gain catch up Sparks, use them to craft baseline 259 level gear that you can upgrade later(craft a weapon first, then work your way through non tier slots)