For your first OU team this is rather good and im loving the differant members that all provide great synergy.
Nearly all weaknesses are hindered by another pokemon and thats great.
But as you are new to OU you will need to understand why these pokemon are in OU as you are using about 2 pokemon completly wrong and 2 others need tweaking in their sets.
Ruenicluss
This set is fine though you may want to consider two changes.
Try flame orb over toxic orb as flame orb provides good team support in a way because it halfs the attack of the burnt pokemon so that would shut down so many sweepers.
Also try psyshock over psychic as that uses your spatk and their def so you can hit chansey and blissey harder.
Salamance
My my my you do need help with this one.
Salamace hits hard and choice band is a very bad choice on it.
It hasnt got the bulk and reliable speed to be locked into a move.
Try Leftovers, Muscle band or Life orb.
Now you can run a dragon dance set which will raise your attack and speed to insane levels allowing you to sweep teams.
Jolly is also needed so it isnt outrun by the other base 100 speed pokemon in OU.
For the set try dragon claw/outrage, earthquake, dragon dance and flamethrower or fire fang.
Flamethrower allows you to hit ferrothorns hard without damage from iron barbs as well as having good power.
Though gets no boosts.
Scrafty
I dont like big roots on scrafty.
It doesnt add damage it just adds healing from drain punch and thats it.
Unless it manages to sweep about five pokemon which is unlikely big root is inferior to leftovers in my mind.
Plus it allows you to die easyer while setting up.
So try leftovers and defintly drop head smash, you will die very easy with it.
Go with crunch as that gets stab and yet covers allot.
Also maybe ice punch over hi jump kick which is very easy to predict so you could easyly find your self with 1/2 hp when they switch into gengar.
Ice punch provides good coverage on most of Ou.
Also just noticed no moxie! Moxie is great as it boosts your attack every knock out which is very easy as after 1 dragon dance you can out speed allot and hit very hard.
Volcarona
I feel sorry for this volcarona as half its set is brilliant then you add solar beam?
Solar beam is one of the worst moves ever unless using it in sun.
Replace for hidden power ice maybe or even hidden power grass if you want an alteranative.
Finally why does it have timid and only 4speed?
Go 4Hp/252Sp.Atk/252Speed speed is essential for sweepers.
Cloyster
This is the sort of pokemon you need to know why its in Ou.
You have given it grip claw? I dont even know what it does but im guessing its not to good lol ;)
Cloyster has access to spikes and toxic spikes.
But and this is a big but, It isnt used for spikes if it was it would probably be in Bl or possibly Uu.
Though it was a spiker in gen 4 in black and white it received a blessing in shell smash.
Shell smash allows you to sweep entire teams lol
It lowers both defses by 50% so thats not that bad you still have 90 base def logicly and it wouldnt suvive a special hit anyway.
But it doubles Atk, Spatk and Speed making it a perfect sweeper.
Try
@Focus sash or Kings rock
4hp 252atk 252speed
adamant
Skill Link
-Shell smash
-Razor shell/Surf
-Icicle spear
-Rock blast
Your set may use its signature move but it hasnt used the signature ability skill link.
This set is now standard and boy it hurts.
KIngs rock is just an idea of mine ;) massive flinch chance for each hit.
Venasaur
He is also a pokemon that you need to know why its Ou and thats because it got a boost in gen5 along with ninetails making a great sun team member doubling its speed and growths effect being doubled.
it doesnt do to well out of sun so its best to replace it or use a sub seed set which is very straight forward where you have defensive stats substitute, leech seed, hidden power fire and toxic.
You will stall well with this and they will die quikly.
Hidden power fire allows you to hit grass types blocking your leech seed.
