Dragon's Approach is pretty bad in this deck. You're not getting to leverage it's second ability by only playing one copy. You're probably better off playing Sarkhan's Triumph, tutor for a Dragon.

You should look for Ancient Silver Dragon, Terror of the Peaks, Goldspan Dragon, Ganax Astral Hunter, Dragon Mage, Dragonlord Atarka, Bogardan Hellkite, Atsushi

You could run one copy of Blasphemous Act in the event that you have Wrathful Red Dragon and a couple of other Dragons. That would be a game ender. 13 damage x 3 dragons = 39 damage you can point at other targets.

Look for cheaper mana rocks like Sol Ring, Fellwar Stone, Mind Stone, Talisman of Creativity/Curiosity/Impulse to lower your mana curve and accelerate your ramp.

You should try to complete the cycles of lands. Fetch: Misty Rainforest, Scalding Tarn, Wooded Foothills; Battlebond: Spire Garden, Training Center, Rejuvenating Springs; Hunt lands: Dreamroot Cascade, Rockfall Vale, Stormcarved Coast; Shocklands: Steam Vents, Stomping Ground, Breeding Pool; Painlands: Yavimaya Coast, Karpulsan Forest, Shivan Reef. These have a higher probability of coming in untapped. If you're going to play dual tap lands, you might as well play the ones that are fetchable or provide some benefit like the scry lands (temple of mystery/epiphany/abandon) dominaria duals (Tangled Islet, Wooded Ridgeline, Molten Tributary).