I am really FED UP of losing on Random Matchup on Pokemon White. I think it's because of my team.

I was wondering if anybody can improve my non-legendary team.

My Team:

Serperior's Moves: Leaf Blade, Giga Drain, Cut, Coil

Empoleon's Moves: Dive, Surf, Brine, Waterfall

Darmanitan's Moves: Thrash, Fire Punch, Flare Blitz, Strength

Gengar's Moves: Thunder, Hypnosis, Dream Eater, Nightmare

Lucario's Moves: Aura Sphere, Me First, ExtremeSpeed

Charizard's Moves: Heat Wave, Flamethrower, Blast Burn

Whoever I think that has given me the most helpful improvement(s) will win a Mew!

I would sugest having your pokemon learn some moves to counter their weaknesses

ffor empoleon you could get some other moves other than water ones, may I suggest an ice move like blizzard or ice beam.
it seems Charizard and Lucario have only 3 moves each, well I suggest you get them some more moves.
hope I helped a bit.

p.s. even if I was the most helpful (in which I wont be) I don't need a mew.

I currently have a losing streak of over 25 and counting in the single battles. q:

Only thing I can think of helping is to replace Cut.

and for empoleon dive and waterfall arnt the best of moves unless you were using them outside of battle (of course)

edit- 150th post

I would suggest building a team of multi-type pokemon, that's what I do. For instance on my team I have Zekrom(dragon and electric) and Victini (Psychic and Fire). Having pokemon that can be super effective against multiple types really helps out.

First off you need a balanced team of 'mon (type wise). You can use Pokemon.Marriland.com - Black / White Team Builde to check strengths/weaknesses. Just keep tweaking until you think you've covered all the bases.
Secondly, I would suggest drastically altering those movesets. You shouldn't have more than 2 moves of the same type (Empoleon/Charizard) or weak moves e.g: Serperior's Cut. Try and keep moves varied type-wise and between physical/special, so that you can hit the majority of pokemon for somewhat decent damage.
I would suggest equipping some of the items (In-battle effect item - Bulbapedia, the community-driven Pokémon encyclopedia) listed here, as they can prove to be decisive in a tight battle.
If you want to go into more depth, you can also try EV training to maximise useful stats, although this understandably isn't for everyone, as it's quite time consuming. (Serebii.net RSCFRLG Pokdex - EVs)

You need FAR more verity in moves. I don't mean to be mean, but you are not at all experienced at competitive battling. I suggest that you watch a couple videos to give yourself an idea of what an average team looks like. YouTube - pokemon competitive battle

Then, I suggest you go to Smogon http://www.smogon.com , a website devoted to competitive battling to put your first team together. They have movesets for all 4th gen pokemon, but unfortunately not all 5th gen pokemon. I also suggest you read a guide on EVs you learn about those, as they are very important.
Serebii.net Games - Effort Values

Just remember - Online Battling is completely different from in-game battling. Your in game team will not win online.

Mine does ...Sometimes

I see what you did there.