Oke, here i have some tips i realised after playing some hours at the game:
1. Buy as many Oran barries as you can, and go to route1, talk to the Miltanks near the Building at the left and make Moomoo Milk. It restores 100hp. As far as i know its the best healing medicine.
2. Warning: this might occur some problems,and i wanna discuss it with someone before you guys use it. So, i went to the Grand Hall, and changed the date to a previous one.That way i could fight with the trainers inside the Hall again. For example if i started playing Poke Reborn at 5/12/14 , i changed the date to 4/12/14 etc . I managed to fight with the trainers a couple of times.not many though.
Sideffects: i am not sure if this is the cause, but my Repels/Super Repels doesnt work anymore..or at least not all the time..
3.About Ev training, i will speak as an example because my english arent very good: This may be some sort of spoil, though you eventually find out at the early stages of the game. So you decide if you wanna read it. Lets say you wanna Ev train a pokemon at Sp.Attack and Speed. Since its difficult to find a place to ev train on sp.attack, you can do this instead. Go to Underground Railnet, the Woobats give you Speed stat.something you need. Now put the item that gives you 4points at Sp.attack. Max your Sp.Attack that way. Then give your pokemon the item that gives you 4stat at Speed. Max Speed too. Done.! My point is that you dont really need a place for Sp.attack(or sp.def/hp) training which is more difficult to find. Places that i call easy are: Underground Railnet for Speed
Onyx Ward Rooftop for Attack Caves for Defense. Use them to Ev train at Hp,Sp.Def.Sp.Att. with the items from Department Store. Thats all for now, if i discover any other usefull tip i am gonna post it:) Tell me your ideas.