If your opponent has a passed pawn on the rook file and they have a rook or queen behind it then this is a really dangerous position. The best thing to do is to avoid that situation. Try not to let your opponent get such a pawn.
If you can't do anything about it then you have to blockade; which means you put a piece on the file that blocks the pawn's advance. In general use your least valuable piece (e.g. knight or bishop) for this.
It depends on the position. Every response has a downside, and given enough time, your opponent will usually be able to create an attack no matter what you do. So you should choose the setup that is the least disadvantageous... not really mind blowing advice is it? 
But to give enough examples to fully answer this, a person could write a book, so it's tough to answer in a forum post... and even in positions where your defense will 100% will give them attacking chances, that defense is sometimes correct because your counterplay is expected to successfully balance it. Chess isn't a game where you can always guarantee your safety. It depends on the opening and the position.
Anyway, I guess I'll post some basic things
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Apparently this isn't even such a strong strategy but I have lost against this attack several times. I have tried just ignoring it and concentrating on building my center. I have tried addressing it exclusively spending all my time on defence of it. Please share some moves with me.
And just a note, an attack on the flank isn't answered by "building" your center, it's (often) answered by counterplay in the center. This means opening lines and actively posting pieces to create threats (or at least to exchange material).
Think of it like water pressure. If the only gap is on your kingside, then all the pressure is released there, but if you open the d file (or any other file, but d or e is usually best), then there are two gaps releasing pressure, so the pressure on your kingside is not as great.
Apparently this isn't even such a strong strategy but I have lost against this attack several times. I have tried just ignoring it and concentrating on building my center. I have tried addressing it exclusively spending all my time on defence of it. Please share some moves with me.