Anyone new to carp fishing is faced with far too many bait choices. I've seen fishermen show up with upwards of dozens of types of baits and scents loaded into a suitcase. It's far too much for fishermen that can only put out two rods. My suggestion is to keep the summer bait choices simple.
Three types of bait work well in the summertime:
1. Doughballs- These are actually breadballs made from the white part of a slice of bread. You can either pack this on a hook and freeline or roll some marble sized balls, let them harden in the sun and use them on the hair rig. This bait works real well where do gooders feed bread to ducks.
2. Maize or Sweet Corn- Corn always works, especially in places where you can prebait or chum ahead of time. I especially like sweet corn on the hair rig, though it can really attract turtles. In that situation, you may have to use maize. If you are into flavoring, try pineapple or another fruit flavor. However, remember that unflavored bait is often more effective than using the wrong flavor.
3. Small boilies- I have written before about the effectiveness of 10 mm pop up boilies. You can add a kernel of sweet corn to this offering or use the boilie alone. I especially like Scopex or pineapple flavor from World Classic Baits.