What to use against Sicilian defense and Caro Kann?

I don't really know what to use against the sicilain defense and Caro Kann after I play e4. I'd like to stick with an e4 opening, but I don't know what to use against those two.

Go with the "easier" stuff to begin with.   Given where you currently are (if your Online rating follows your playing strength) there are so many things you need to get better at before spending time studying openings deeply. 

Just go after low-theory (relatively, speaking) openings with clear ideas. Given that you are an 1.e4 player, you probably prefer open positions as opposed to closed ones.

Consider playing the Exchange variation (1.e4 c6 2.d4 d5 3.exd) followed by the Panov-Botvinnik attack with 3.c4.

  For the Sicilian, either try the Morra gambit (1.e4 c5 2.d4 cd 3.c3) or if you want to play it safer, the Alapin (1.e4 c5 2.c3) ... Simple ideas that should help you transition to a playable middle-game against the kind of opposition you are currently facing.

Once again, these ideas worked for me *so far* and I should think they might help anyone with not enough time to invest in diving into theory. Good luck!

Shivsky makes good points.  At least for the caro, i would encourage you to look deep as there are many roads here that black may not be familiar with.  Beginners (like myself) do not need to play GM mainlines.  Are GM mailines sound?  Of course, why else are GM's playing them, but are they your only option?  No.  The caro (from white's side) has a ton of variations that arise after e4 c6.  Some may work for you and some may not.  Either way, try them.  One of my recent favorites in the caro is e4 c6 d4 d5 Nc3 dxe4 f3! where white gambits a pawn for rapid development.  If black isn't ready, bad things can happen.

Against the Caro, if you don't mind studying some theory and playing a well known main line, then the Panov Botvinnik is a good line to consider.  A peculiar line that I used to play was: 1.e4 c6 2. d4 d5 3. e5 Bf5 4. h4!  The move may look crazy but it is not main line stuff and will probably surprise your opponents.  For several years this was my main line against the caro and I beat some 2000+ rated people with it.  It's a fun and different kind of line.

Against the sicilian, either study and learn the dragon or play the alapin which is much easier.

 Actually , in the advance variation of the caro kann 4 h4 is quite known and the third most played move in the position, with 4 Nf3 and 4 Nc3 being the only moves played more in that position. Tal used to play 4 h4 in this line quite a bit I believe.

The OP is asking what to play ( as white ) against the sicilian(s) and you seem to recommend playing the dragon ? This is confusing. Are you saying he should just learn how to play against the dragon and assuming thats the only sicilian(s) he will face ? I agree that the alapin  is a good choice against the sicilian. I think its best to avoid the open sicilians unless you have a LOT of time to keep up with the theory on ALL of them..... they are very sharp and there is a lot of theory on many of them : dragon, najdorf, sveshnikov, classical, etc.

I would suggest the OP learn the exchange variation against the CK and the Alapin against the sicilian.