You might want to try using fonts like Anime Ace 2 or Manga Temple next time. Look up fonts at blambot.com
Don't use smileys in your scans, for the love of porn, just don't.
Watch out for grammar, there's a lot of mistakes.

Base +8, hurpa +5, Palaxius +1, TempRarity +6, ImperialDragon +4

Let's assume you are the translator, like you said (can't check as your nick here differs from the one on page 02)
...
First of all, i don't know the original for this one and my japanese reading-skills are extremely limited.
That being said, your translation does not sound very off to me.
Some things you should be working on for future releases:
- Cut the Smilies, they don't fit and make the translation look like an sms or chat-room-log
- Similar with the hearts. Don't color them. Looks off in a black&white-work
- Revise your english (you already mentioned that yourself), there are a lot of mistakes throughout the pages, grammar, diction and spelling
- It's just a personal preference, but change "Sister" to "Onee-Chan"

All-in-all it's well done for a first translation. Keep working on it and in time you'll become a good translator.

Base +8, hurpa +5, minin7 +6, Daikengo +10, blademaster99 +5, jerieljan +4, ImperialDragon +4, Kantzakolt +1, crucialmomment +1, guy11 +7, Kanti-kunj +7, Quake91 +8, KingMe42 +5, and 3 more...

It's a very good for your first try so keep working.

Base +9

Remove the smilies.
It's unprofessional and makes it look like a teenager did it.
Use "Onee-Chan" because honestly, she's not his sister.
She's a friend that he looks up to, and whenever that happens, they tend to call them "onee-chan" or "onii-chan".
Cause if he calls her his sister, then it really gives the impression that she's his sister, and it's incest. But it's not.
There's some words that could be replaced. Like using "Coincidence" instead of "Happening", but it's never easy to translate between languages without triple checking for any grammar mistakes.

Base +4

raw here http://g.e-hentai/g/339332/e30863cdf5/

Base +27

@Karshu
Maybe he IS a teenager :P

Base +7

The smileys are dumb and distracting.

Base +5