One way way to try and determine that is by comparing how Premils interpret these events as opposed to how Amils interpret them. Then seeing which view is agreeing with what the text indicates, which includes events that involve chronology. For example, verse 2 as opposed to verses 16-19. Would anyone argue, chronologically speaking, that verses 16-19 can be fulfilled before verse 2 is even fulfilled first? It would be like arguing that Christ's 2nd advent can precede His 1st advent. Clearly then, when it comes to events in the Bible, especially in regards to prophetic events, chronology matters, thus is relevant.
And what do chronological events do? They lead from one thing into another, etc.
Zechariah 14:1 Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.
2 For I will gather all nations against Jerusalem to battle; and the city shall be taken, and the houses rifled, and the women ravished; and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city.
3 Then shall the LORD go forth, and fight against those nations, as when he fought in the day of battle
One thing that is already crystal clear here, none of this can be involving 70 AD. For example, compare the following.
and the city shall be taken, and the houses rifled, and the women ravished; and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city.
With that of this.
Luke 21:5 And as some spake of the temple, how it was adorned with goodly stones and gifts, he said,
6 As for these things which ye behold, the days will come, in the which there shall not be left one stone upon another, that shall not be thrown down
Luke 21:20 And when ye shall see Jerusalem compassed with armies, then know that the desolation thereof is nigh.
21 Then let them which are in Judaea flee to the mountains; and let them which are in the midst of it depart out; and let not them that are in the countries enter thereinto.
Does it sound like any of that fits this---and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city
Obviously then, since Zechariah 14:2 can't logically fit 70 AD, it still has to fit somewhere, though. It shouldn't take a rocket scientist to figure out, that if it can't fit 70 AD, it has to fit an era of time post 70 AD.
The question is, is verse 2 supposed to be interpreted in the literal sense to begin with? Is it involving literal Jerusalem in the middle east being literally surrounded by all nations on the planet? If we factor in verse 4, how can Jerusalem not be understood in the literal sense here? Is there a way to understand the mount of Olives, which is before Jerusalem on the east, in a sense that is not even literal? Do things pertaining to the non literal typically involve compass directions? Is it literally true that the mount of Olives, that it is before Jerusalem on the east?
Zechariah 14:4 And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst thereof toward the east and toward the west, and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south.
What should we make of this verse, keeping in mind that chronology is relevant here. IOW, we can't have this verse meaning during a time when Jesus literally walked upon the earth prior to His death, then have verse 2 involving an era of time post his death, and that we then think that makes good sense of the text. Because, clearly, verse 4 is pertaining to verse 3 and that verse 3 is pertaining to verse 2. That's how chronology works, as in, how one event leads into another event, so on and so on.
I think I will stop here for now. There's a lot more to discuss/debate involving this chapter. But first we need to make sense of these first 4 verses before we can try and make sense of any of the verses that follow.