First off, don't even worry about reading 'gmat like' things for now, Dinesh. Read novels, read stories, read articles--just read anything to get your thoughts 'into English,' every day, so that turns of phrase like this become more familiar to you. You don't need GMAT texts for this, you just need English texts.
But regarding this sentence you referenced here--my old advice applies. If you don't know a word in a sentence, look at the words you do know, and break down those meanings to see what you can get from context. (Note also, this sentence is from the GRE, in a question type that has students choose a word to fill in the blank. So the fact that you don't have a word there is an added challenge).
But look at the sentence. Ignore the 'far-reaching' part for now.
“the most far-reaching campaign finance reform will fail to ______ the influence of money,”
What thoughts can I pull from the sentence? Start with the VERB. I know that [something] will FAIL to [affect somehow] the influence of money. So, in general, there's *something* the writer thinks could [affect in some way] to the influence of money... but it won't.
What is the 'something?' Well, the "most [far-reaching] campaign finance REFORM."
So some kind of REFORM (the 'most [new word] campaign finance reform') WILL FAIL TO [affect in some way] the INFLUENCE of money.
I have a pretty dang good idea what this sentence means now, without knowing the specifics.
With a few more context clues, I could figure out what 'far reaching' means. For one, the full sentence starts with 'even': "EVEN the MOST far reaching campaign finance reforms WILL FAIL TO _____ the influence of money." That word 'Even' means that the writer is trying to show 'HOW CRAZY THIS IS!'
'HOW CRAZY IS IT that the MOST far reaching campaign finance reforms WILL FAIL TO _______ the influence of money.'
If it's 'crazy' that these finance reforms WILL FAIL, that means they are the ones MOST EXPECTED NOT TO FAIL! So 'far reaching' must be something like 'does the most to achieve the goal.'
So now I can untangle most of this sentence (except the blank word).
There are some campaign finance reforms that are most able to DO [something] to the influence of money...
Even those reforms will fail at DOING [that something].
What that 'something' is a GRE question, not a GMAT question. (I suspect it's a word like 'diminish.' The GMAT would not leave this verb out, but even without it, I can get the gist).
Start with VERBS of a sentence. Understand what that verb is. What SUBJECT does that verb? This will be a huge part of the battle.