GRR!!! I made a long post on that "team worth fighting for" thread yet that mod locked it. BAH!!
Anyway, here's what i was going to say in short.
Btw, this is for an oversued tier battle. Btw, this is assuming your game is platinum.
Azelf > Gengar/Alakazam
Graveler > Rhyperior/T-Tar/Salamence (Garchomp is in the uber tier)
Manaphy > Gyarados (You can catch Lv.1-100 Pkmn in Resort Area)/Floatzel
Infernape > Infernape
Luxray > Electivire/Porygon-Z (discharge/thunderbolt)
Staraptor > Skarmory/Roserade.
I'll explain my recommendations now.
Gengar/Alakazam - Powerful Special Sweepers. Fast and powerful, but frail.
Rhyperior - 'Solid Rock' which halves super-effective moves + nice move pool + awesome stats
T-Tar - Awesome stats + nice move pool
Salamence - Maybe you want a dragon in your team? Salm has great stats.
Gyarados - Nice move pool and stats.
Floatzel - No 4x weakness, quick, powerful, nice move pool.
Infernape - Awesome move pool, Great Typing, Fast.
Electivire - Awesome ability (Motor Drive, which boosts speed once hit by electric moves), good stats and nice movepool.
Porygon-Z - It looks sick + Comparable-to-Alakazam/Gengar Sp.Atk + AMAZING Move pool + Nice "Download" ability + It can take the place of an electric type with Discharge or Thunderbolt.
Skarmory - Awesome defense. Stealth rock. Only two super-effective weaknesses.
Roserade - Well, you don't have a grass pokemon (if no grass, give Gengar/Alakazam energy ball). Roserade has all-around stats and "Natural Cure" ability. Again, this has a nice move pool as well.
I Hope this helps you in your jump to the competitive battling scene! Change your team little by little. Baby steps. It's a pretty difficult feat to obtain these pokemon, let alone fully evolve them and then EV train them (I Hate EVing. ugh), so good luck!
P.S: Here's a site to help you on your EV Quest. It's a long read, but it's helpful. Before I truly understood EV Training, I thought it meant battling level 20 pokemon over and over again to get some minor stat boosts when you level up. This makes it so much easier. so much.
http://serebii.net/games/evs.shtml