[2020] Help me form a strategy for DXP? New player with a semi-plan.

For Smithing, I'd recommend always training in the Falador Artisans' Workshop on world 70, to benefit from luminite injector buffs and earn respect towards unlocking benefits from Egil's shop, like the blacksmith's outfit (the helmet upgrade also provides daily free coal and teleports to the Workshop).

https://runescape.wiki/w/Pay-to-play_Smithing_training has a handy list of items that improve your Smithing efficiency, such as Varrock armour and an auto-heater.

Smithing and sacrificing fully upgraded burial armour sets in the Artisans' Workshop gives chunky spikes of respect and XP https://runescape.wiki/w/Burial_equipment

I'd also recommend Doric and Boric's tasks after the What's Mine Is Yours quest. https://runescape.wiki/w/Doric_and_Boric_tasks They provide some good milestone goals and bonus XP to work toward while leveling your Mining and Smithing. Miniquests are in the quest list now, to help keep track of their requirements.