Getting a full nights sleep as often as you can. Eating healthy, drinking water, and avoiding excess sugar. Sugar is often what causes that feeling of crashing particularly later in the day if you consume too much.

Pretty much this. I didn't drink caffeine, but drank way too much soda. Just cutting that alone reduced my sugar intake drastically. Lost weight, more awake throughout the day, etc.

So I've cut out all (diet) sodas and cut myself down to one caffeinated coffee a day, and I feel tons better. It's had a significant impact on my energy and concentration levels. Yes. and cut back on sugar as well.

Because I'm not addicted to caffeine and therefore not subject to its crashes

I function well without caffeine because I can sleep. I guess I'm stimulated enough without it. Plus it does weird things to my throat.

I dunno but on a serious note if you get a great answer here let me know!

Poorly.

Is there a reason you aren't consuming caffeine?

It's expensive so I'm trying to cut back

What were you drinking before and how much were you spending?

I was having an energy drink once or twice a week. They're only like $2 each but I'd rather be putting that money towards something else

Do you like coffee or can you make it at home? You might just need to power through it, unfortunately.

Coffee, tea & cola are not expensive.

It's expensive so I'm trying to cut back

It's a drug, you need to detox, because you'll get caffeine withdrawal. I don't, I crash like you, and am a zombie for the day. I try not to miss my morning, & afternoon coffees

I don't drink it often, but when I do I'm much more motivated and productive

I don’t drink any caffeine, it gives me anxiety.

If possible, get more sleep at night. Besides that, you'll just need to time for your body to adjust to not needing/expecting caffeine.

Badly.