lol funnily enough I made a thread about how I need to improve in Tower Control right before you made this thread about how to improve in Splat Zones. So Splat Zones is actually my favourite ranked battle game-mode so I think I will be able to help you out.
So what I normally do at the start is take the most direct route to the Splat Zone and attempt to splat any enemies while simultaneously covering ink, I'm able to do this effectively because I use the 96 Gal Deco which has good range and also has the Splash Wall, this works really well for maps with one relatively small zone such as Blue-Fin Depot and Walley Warehouse. This is a bit harder to accomplish if there are two zones like Blackbelly Skatepark or one big zone like Kelp Dome, in these instances I play slightly more defensively and stealthily. If however I decide to use a short range weapon like the Tentatek (or in your case the Luna blaster) I would usually instead attempt to flank around and let the longer range weapons draw the enemy fire.
From here the two most common scenarios are:
1. You capture the zone more or less and take care of any stragglers. From here your two main objectives are to stay alive and guard your zone, fairly straight forward.
2. You fail to capture the zone, if this happens follow the steps that I mentioned earlier and either try to flank or draw enemy fire for others to flank. DO NOT engage the enemy alone, when attempting to re-capture the zone always make sure you have at least 3 other team members with you, 4 is definitely better though.
There are a couple more specific techniques that I implement such as hiding, more so than the other modes. When I do this though I usually try to be in a secluded spot, I only come out if I think I'm going to be splatted or if my team is making a good push. Related to that point is that if we make a push and fail then I don't necessarily retreat, again if I'm in a secluded spot with a relatively low chance of being spotted then I might just wait there. One more important thing, whenever possible DO NOT stand in your own splat zone as if you get splatted then it will create a large puddle of enemy ink in the zone which is very bad, again related to that point is don't super jump into a splat zone unless it's under your control.
That basically wraps it up for this guide to Splat-Zones, hope this helps! You should note that this is by no means the perfect model guide, after all I'm only an S player, I have yet to hit S+. For more general gameplay tips I strongly reccomend you check out the other guides in Squidboards, you might also want to take a look at Nintendome', 'ThatSrb2Dude', 'Squidkids', and 'Squids Next Door' . Good luck!