If you're new to competitive play, I recommend doing some reading before teambuilding. Your first builds are going to be very rough (and this team is not very good, to be sure) but you can mitigate that with an understanding of the metagame. Read:
* Ubers analyses:
https://www.smogon.com/dex/sm/formats/uber/
* Usage stats (especially the 'moveset' directory):
https://www.smogon.com/stats/
* Ubers subforums on Smogon, e.g. viability rankings.
Here is some other loose advice:
- Play with your team yourself before you ask other people to rate it.
- Mega Rayquaza is banned in Ubers.
- Don't pick moves for their luck-based secondary effects. Ancient Power, Dark Pulse and Ice Fang are not good choices where you've used them. Thunderbolt happens to be OK coverage on Kyogre, but it's outclassed by Thunder.
- I feel like you've deliberately put one Pokemon with each weather setting ability into this team. In any case, that is not a good strategy. You should not be thinking about that when you're teambuilding.
- Coverage moves on offensive Pokemon are for hitting Pokemon that wall/resist your most powerful attack. The priority is not to have a super-effective attack for Pokemon you match poorly against defensively (though often there is overlap). This is why you should use V-create instead of Blizzard on Rayquaza, for example.
- Justify your choices more than just saying 'Brick Break for shields'. We know what the move does -- *why* do you want that effect instead of others? Are screens particularly common in Ubers?
- Offensive Pokemon with four attacks and no means of boosting their power are impotent. I wouldn't call four-attacks Tyranitar a 'staller' either.
- Ninetales is a bad pick for Ubers, and Leafeon is even worse. Resist the temptation to use personal favourites, and if you must, build around them in a format where they make sense.
- Choice Band + Protect + Synthesis is less than ideal.
