ἀμήν
I have found this from atticgreek.org to be helpful: http://atticgreek.org/downloads/Transitioning.pdf
The best piece of advise I have gained from there is to read the (English) introductions and commentaries, and also to research the subject matter and history a little before reading the Greek text, as one you know the context it becomes a lot clearer what is going on without needing to turn to lexicons and translations too much -having an idea of what they are going on about already mentally prepares you for what to expect.
For example, having recently bought the Cambridge Yellow/Green Lysias speeches, a quick check of the commentary (just the first few paragraphs) telling me the court case was about a family dispute made the Greek text much clearer (still very difficult for me to read, however!).
As some have mentioned, having an English translation too close to hand raises too much temptation to keep checking every other sentence, which in the long run probably isn’t helpful!
Andriko - Totally agree. I’ve found that even reading some wikipedia links ahead of diving into a work (e.g., on Xenophon and various personages in Peloponnesian War prior to reading Hellenica) makes it way easier to follow who the various people are and what’s going on.
Thanks for the link. 
One thing that Hyplern does pretty well is its popup mode which lets you see the translation of just the word you are mousing over. (It can also show the translation of one word you’ve clicked on—but only for a few seconds, which is not so great.) Unfortunately there’s no Ancient Greek material on Hyplern yet, it seems.
The ios app attikos is very helpful. Ditto the volumes in the Loeb Classical Library.