Nexus is defiantly right and since you are playing on the console the Gravitational Potions don't literally turn your screen upside down and ironskin will save your life however my question is what weapon and armour are you using since The Destroyer is the easiest mechanical boss and The Twins are the most difficult mechanical boss since when they reach there second stage both eyes are extremely tough and difficult to kill. My best suggestion is that you focus on killing The Destroyer, using the souls of might to craft the Megashark (easily the number one gun to use on console) and the hallowed bars to start making some hallow armour (focus on the defense for solo work)
Then make crystal bullets like Nexus said since they only require crystals and musket balls which are dirt cheap to buy. Afterwards fighting both Skeletron Prime and The Twins should be an easy task with the Megashark and some wings
i dont think hallow bars exist on console version
Gun:Zealous clockwork assault rifle
armor :mythril set
potions:bowl of soup, ironskin, swiftness, mana damage boost, and thorns potion
Gear:wings,thing to increase invincibilty, obsidian shield, speed/rocket boots, cload in a bottle
arena: I decide to use wall of flesh arena since IT gives me a better dodge chance than anything else.