I think just about every seriously chess player is less prepared for both 1. c4 and 1. f4! 1.c4 is a much more serious try than 1. f4. Against 1. f4, I would simply recommend 1. ...d5 followed by 2. ...g6, 3. ...Bg7, 4. ...c5, and 5. ...Nc6 with an equal game. Against 1. c4 white can adopt many setups, however, it is useful to find out if what you play against 1. d4 has some possible similiarities to a possible 1. c4 continuation as they may transpose. (i.e. A Caro-Kann and Slav player may choose to play 1. ...c6 against the English). Hope this helps!
Best Response to White C4 or F4 Openings?

ive always had trouble against the english, don't really enjoy anything that is on offer.
The + side is black has many reasonable options against 1.c4 and 1.f4 setups and its mostly a matter of taste.
I play the symmetrical against the english (c5, g6, bg7, nc6 etc)
and froms against the bird (objectively probably not best).
First of all 1. c4 is a very serious opening allowing white to really play for the advantage. The many possible transpositions to other openings make it one of the hardest openings to master. Personally I play e5 and the revered sicilian against the english (e5 / Nf6 / d5 / Nxd5).. And although it might sound like the sicilian it is not even close. It is a fairly easy system to learn and not that easy to combat as white.
f4 is a much less serious opening and often lets black equalize quite easy. My personal favorite is with d5 and Bg4 (with the idea to trade the knight before it can jump to e5).
I always play 1. c4 and usually 2. NC3, it's a very interesting opening and many players aren't prepared well for it. If my opponent play 1.c4 , I'll answer 1.. c6 , because I like Slav defense and Caro-Kahn. And I don't like then answer is 1..c5, in this case it's hard to get advantage for me.
If my opponent will play 1. f4 - I'll be happy with 1... d5 :)

Tony Kosten (author of "Dynamic English") said that don't play the Reversed Sicilian(1.c4 e5) if you don't like to play the white side of the Sicilian.
Well, that's not the exact words but something like that :D
what he said was more along the lines of how amazed he was at the number of people who play 1. d4 to avoid playing the white side of the sicilian who are more than happy to reply to 1. c4 with e4 and get the same position down a tempo! iirc of course.

"It has often struck me as strange that so many players are happy to reply 1.c4 with 1..e5 and yet are unwilling to play 1.e4 themselves. It appears very odd that they are happy to play the black side of the Reversed Sicilian and not the white side of a normal Sicilian, a whole tempo up."
- Tony Kosten
There, I found the exact phrase :)
Though there might be some overlap between the sicilian and the reversed sicilian the difference of one tempo matters a lot. (Please note that I only play the reversed sicilian versus g3 setups and that is 80% of the time)
- For one black cannot copy the traditional white pawnstorm against the dragon and has to opt for more quiet play. This often means castling short instead of long and this means a whole different strategy from both parties.
- While in a sicilian white often tries to avoid massive exchanges on d4 because it will diminish his advantage in the reversed sicilian black is more than happy to exchange on d5 as it brings him closed to equality. So here it is white who actually would try to avoid exchanges on d5 allowing black free piece movement.
- Having a tempo more does not mean having the advantage. In the sicilian black often delays development of his queen side knight because this forces white to keep in mind that the knight can come to d7 too. In the reversed sicilian the knight is often already placed on c3 giving black some extra posibities.
- The sicilian is mostly a counter attack opening. Black chooses his attack based on the setup white chooses. Did he play f4, did he castle long, whte did he develop his white (and dark) squared bisshop. In the reversed sicilian white is always first to move and black can respond. This prevents white from choosing the perfect attack setup.
In short the reversed english is a very interesting opening and certainly some ideas on how the sicilian works will help but playing with a tempo less does have it's merrits in this kind of situation
I play the Nimzo Indian and love it but i do avoid Nf6/e6 lines against the c4 as i do not really trust black after 1. c4 Nf6 2. Nc3 e6 3. e4 (the Minekas variation). It is a really dangerous system and even with good play for black I rather play white.

Vs. 1.f4 I like 1...c5 since it's recommended by De Firmian. Against 1.c4 I sometimes set up a Queen's Indian setup or play 1...e5 because of the potential for imbalances. The reversed dragon is tough from either end of the board however.

"It has often struck me as strange that so many players are happy to reply 1.c4 with 1..e5 and yet are unwilling to play 1.e4 themselves. It appears very odd that they are happy to play the black side of the Reversed Sicilian and not the white side of a normal Sicilian, a whole tempo up."
- Tony Kosten
There, I found the exact phrase :)
Wow he described me ^_^

I think just about every seriously chess player is less prepared for both 1. c4 and 1. f4! 1.c4 is a much more serious try than 1. f4. Against 1. f4, I would simply recommend 1. ...d5 followed by 2. ...g6, 3. ...Bg7, 4. ...c5, and 5. ...Nc6 with an equal game. Against 1. c4 white can adopt many setups, however, it is useful to find out if what you play against 1. d4 has some possible similiarities to a possible 1. c4 continuation as they may transpose. (i.e. A Caro-Kann and Slav player may choose to play 1. ...c6 against the English). Hope this helps!
Why do you give 1.f4 a ! It's the worst opening outside of the A00 complex!
I think exclamation mark was meant to end the sentence, not to show that 1. f4 is particularly good first move.

The best response(s) to an opening is/are the one that works for you. The worst response(s) is/are the ones that don't work for you
Don't hold your breath expecting total strangers to (correctly) answer questions you need to answer yourself.
"Best" and "worst" openings depends on which openings suit your skill, style and experience. First you need to figure out do you prefer playing open, semi-open or closed games? Do you prefer to attack, defend or counter-attack? What do you know about basic opening and endgame (yes, endgame) principles? What do you still need to learn? etc etc
http://blog.chess.com/NimzoRoy/chess-opening-principles
http://blog.chess.com/NimzoRoy/endgame-faqs
PS: Contary to what many nimrods and patzers will tell you, basic endgame principles are VERY important and often apply not only to middlegames but openings as well
hi. new player here.
just curious what BLACK's best responses are to WHITE opening with pawn either C4 or F4?
I'm just not used to these opening as much and my counters don't seem very good. I often find myself in awkward positions.
so just curious how you guys would handle these two moves? I'm so far just more used to WHITE going E4 or D4...but less prepared for these two.
thanks very much in advance!