Super wet reverbs are your friend.

Try placing a 75-100% wet reverb on your vocal track, or setting the reverb send pre-fader and keep the volume of your vocal track down.

Try using this technique on one snippet of your vocal looped. For example, an 'ooh' or an 'aah' looped throughout your drop very wet in the background can really fill out a mix and achieve the thing you mentioned.

Before I start I want to make the point that there are LOADS of ways of mixing two synths together that may hit similar frequency areas. This is simply using the examples you gave me and saying how they mixed their arp.

The three main things I would bring up are firstly your arp is a lot wetter than the other examples you gave. The supersaw is also very wet, meaning they both sit back a little to the same degree. Maybe consider drying your arp so that it hits harder to the listener. Secondly, you can consider panning. Now, I wouldn't say hard panning, but just push it slightly to the left or right. Alternatively, duplicate the arp so that you have two of the same, and hard pan one to the left and one to the right, see how that sounds. Thirdly, and potentially your best choice, would be to make your arp more 'pluck-y'. This seems to be an effect used by both examples you gave. All it entails is using the mod env on the oscillator(s) pitch, then adding a slight decay (by slight I mean <150ms). Experiment with this, and you'll find you get a nice sharp attack to the synth that can make it cut through the mix nicely. One thing to be wary of with this is if you have heavy compression on the synth, as that can destructively alter the effect. Try experimenting with no compression on your effects chain if you have some, as it will give you a more accurate idea of whether the effect is working.

Hope this helps

That pitching effect on the synth in the beginning is all to do with the mod env attached to the oscillator pitch. The easiest way, if possible in whatever synths you use, would be to set the mod env to -100; essentially reverse the direction of the mod env's ADSR. Then set the decay to around 450ms and the attack to around 100ms and you've got the effect!

P.S. I recreated the synth in reason's Thor synth, so here's a screenshot for you to translate over to other synths
P.S. This is without EQ, reverb or compressions which you would defo need to add. Let me know if you need the settings for them and ill let you know what I did.

So I assume people have gone off this idea?

No, really. People totally underestimate fletcher-munson curves.

Here's a trick: Pick bunch of reference tracks (so in your case your favorite LOUD AF tracks), lay them down in your DAW, shift them so the loudest parts play at the same time and then solo one after another to check the difference. ...but! Instead of looking only at volume or RMS measurement, fire up spectrum analyser. ...then compare those tracks with your music. I bet you'll see huge portion of high-midrange information that's probably missing in your tracks (as you made the BASS so loud).

It's really common mistake. I fight it too to some extend. At certain point you just realize how harsh those loud tracks sound anyway, so you stop trying, lol. Skrillexe's Bangarang for example. So much highs. Such a cool track otherwise...

Simply said: I'ts all about balance.

Yo cheers for this advice, I'd never think of doing this.

Well, first off I'll quote (without using the quote function as I can't find the thread!) one of the most beloved sentences in this forum. 90% of mixing is simply adjusting each tracks volume level.

The following is just my two cents. When it comes to using the sliders on the in DAW mixer, they may not be entirely accurate as you have volume functions elsewhere, e.g. the synths themselves. Therefore, never trust that the volume slider being at -6dB means the volume has been reduced that much.

I'm a big fan of mixing around a focal point. So, for most of my tracks that is the kick drum. Therefore, I'll set my kick to -6dB or -10dB or whatever you want, then mix everything around that without thinking about every volume level. That way, I've effectively got the headroom I need as the focal point brings all the other levels down.

Final note. Never adjust the master slider. If you're looking to boost volume more overall, look through the sound wars and mastering topics. The only time I'll adjust it is with automation in order to make a small section of my song, with lots of layers, intentionally quiet.

Hope this helps! 

Can anyone figure out the lead to Armin van Buuren & W&W - D# Fat? (https://www.youtube.com/watch?v=VVoiG8LEQ8c)
I cant find a wave form that makes the sound specifically and a pitchbend saw is giving mixed results.

This tutorial gives you the basics: https://www.youtube.com/watch?v=i8pvL_LY6Os
However, it would still need a little tweaking.