ir vs venir
Spanish anchors movement to where the speaker is right now — the opposite of English more often than you'd think.
ir
To go — movement away from the current location of the speaker.
Voy al mercado.
I'm going to the market.
Speaker is leaving from where they are. Standard use.
¡Ya voy!
I'm coming! / Coming!
Spanish says 'I'm going' even when English says 'coming.' Because you're moving away from where you currently are toward them.
Fueron a Barcelona el verano pasado.
They went to Barcelona last summer.
Movement to somewhere away from the reference point — even in the past.
venir
To come — movement toward the speaker's current location.
¿Vienes a la fiesta?
Are you coming to the party?
The speaker is at (or going to) the party. They're inviting you to join where they'll be.
Ven aquí.
Come here.
Movement toward the speaker. The most basic use.
Vengo de trabajar.
I'm coming from work.
Venir de = coming from somewhere. The movement ends at the speaker's current position.
Tricky bit
On the phone: '¿Puedes venir?' (Can you come here — to where I am?) vs '¿Puedo ir?' (Can I come — to where you are?). English uses 'come' for both. Spanish tracks the speaker's anchor point.