Hi, I am new here in this forum I just want to know what should I do to improve my team. Any tips will do, here is my team.

Name: Heracross
Nature: Adamant
Ability: Guts
Item: ??? - I don't know what to put.

Stats: Moves:
Hp: 302 Rock Slide
Atk: 360 Earthquake
Def: 173 Reversal
Sp.Atk: 102 Endure
Sp.Def: 224
Spd: 262



Name: Ludicolo
Nature: Modest
Ability: Swift Swim
Item: ??? - I don't know what to put.

Stats: Moves:
Hp:299 Rain Dance
Atk: 156 Surf
Def: 172 Giga Drain
Sp.Atk: 306 Ice Beam
Sp.Def: 247
Spd: 177


Name: Kingdra
Nature: Modest
Ability: Swift Swim
Item: ??? - I don't know what to put

Stats: Moves:
Hp: 315 Rain Dance
Atk: 201 Surf
Def: 220 Ice Beam
Sp.Atk: 317 Substitute
Sp.Def: 226
Spd: 196


Name: Starmie
Nature: Modest
Ability: Natural Cure
Item: Shell Bell

Stats: Moves:
Hp: 261 Psychic
Atk: 154 Surf
Def: 180 Thunderbolt
Sp.Atk: 322 Recovery
Sp.Def: 177
Spd: 313


Name: Houndoom
Nature: Timid
Ability: Flash Fire
Item: ??? - I don't know what to put.

Stats: Moves:
Hp: 260 Sunny Day
Atk: 175 Flamethrower
Def: 131 Solarbeam
Sp.Atk: 309 Crunch
Sp.Def: 190
Spd: 294


Name: Salamence
Nature: Modest
Ability: Intimidate
Item: ??? - I don't know what to put.

Stats: Moves:
Hp: 316 Dragon Claw
Atk: 261 Flamethrower
Def: 193 Crunch
Sp.Atk: 342 Hydro Pump
Sp.Def: 185
Spd: 282


Well, I know that half of my team are water type I just actually like water-type Pokemon.
And yes, I knew that almost all are in Modest nature which is a sweeper type.

I need your tips on items and moves! or anything you want to change in my team.
( I got a big trouble with Heracross when it comes to double match )

Thanks in advance!