I'm going to make some suggestions assuming that you want to keep the deck Casual [and very budget/affordable] but help trim down to the minimum of 60 to increase efficiency.
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Assassin's Strike and
Consign to the Pit are just way too mana intensive for what they do. Your removal should either be of a lesser converted mana cost [CMC] or provide more bang for the buck. I'd cut both.
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Aid the Fallen, or effects like it are fine for a casual deck but I'd trim down to just one copy.
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Barrier of Bones, walls are probably not where you want to be in a deck with these 2 colours, I'd cut both.
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Gilded Lotus, a great card but probably more suited to a Commander deck. Artifacts that produce mana are good but for 60 card casual I'd look for something more like
Rakdos Signet-
Douser of Lights, while a sturdy creature, doesn't do anything, I'd cut.
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Fire Elemental, for the same cost you could have more
Demanding Dragon, I'd cut all of the Elementals and add one more Dragon [if you have or can get]
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Kaya's Ghostform, fine for casual but I'd cut down to 2 at most and only because I'm assuming you want to keep some focus on your Chandra planeswalker.
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Karplusan Hound, with only one copy of your planeswalker, I'd cut down to 1 or 2 copies.
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Gravewaker, fine as a one-of but the activated ability is expensive so multiple copies don't do a ton for you.
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Price of Fame, its usefulness will depend on how many legendary creatures your opponents are playing. Better in a Commander deck. I leave it up to you to assess how valuable these are going to be based on what your opponents will typically be playing.
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Goblin Assailant, while having great flavour text, doesn't do anything. I'd replace with something like
Burning Prophet or
Cult Guildmage. Any 2/2 for 2 mana that has some sort of ability is an upgrade.
The cards in your deck that I think are the best choices are:
Demanding Dragon,
Lava Coil,
Ravenous Chupacabra [I'd look to get one more and replace something with it] and
Charging Monstrosaur [2 is probably all you'll want for the deck]. Your deck, however, lacks card draw. Inexpensive options include:
Theater of Horrors,
Skeletal Scrying,
Promise of Power and
Sign in Blood.
In a 60 card deck, depending on the overall costs of your spells, you'll want to go to 22-24 lands. It looks like you've got more black mana requirements so I'd keep more swamps than mountains.
I didn't address every card but made some suggestions to help whittle down the size of the deck so that it plays more consistently. I also didn't count every cut I suggested but suspect that you'll need to make the last few after some game play tells you what effects you like and what is working for you vs what isn't. If you're interested in more powerful options [read, more expensive], I can suggest some that aren't break the bank bad. Hope this advice helps and welcome to MTG!