Using Warp effects in Illustrator:
Overview:

( 1. ) Using WARP tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 2 positions.Final image:

Warp tool can be used to give sharp end corners to shapes. Let us see various positions of using the tool. First open a new document of any size. Use the shape tool and select the star shape. I chose this particular shape because it has good corners to demonstrate this tool better.
(a.)Warp tool by clicking inside the shape and dragging towards outside: Click inside the shape as shown in the image below (click where the star is placed) and drag towards outside without removing your finger from the mouse. Refer image A.
(b.) Warp tool by clicking outside and dragging towards inside: Click outside the shape as shown in the image below (click where the star is placed) and drag inside the shape without removing your finger from the mouse.Refer image B.

( 2. ) Using TWIRL tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 3 positions.Final image:

Twirl tool can be used to give constructive circles. Let us see various positions of using the tool. First open a new document of any size. Use the shape tool and select the star shape.(a.) Twirl tool by clicking in the corner of the shape : Click ON the shape outline  as shown in the image below (click where the star is placed) and keep pressing for some time. Do not remove your hand from the mouse. The longer the time you keep pressing, the more circles you will have.Refer image A.
(b.)Twirl tool by clicking inside the shape and dragging towards outside: Click inside the shape as shown in the image below (click where the star is placed) and drag towards outside without removing your finger from the mouse in the left direction then drag towards the right direction without removing your hand from the mouse. You can drag them in the opposite directions also, like first right and then left.Simply dragging in one direction will not give a good curvy look. You might have to drag couple of times in different directions.  Refer image B.
(c.) Twirl tool by clicking outside and dragging towards inside: This is very complicated as you will not get a neat twirl for this. You have to be very patient while moving the mouse.You might have to try moving in different directions many times experimenting, to get a better twirl.Click outside the shape as shown in the image below (click where the star is placed) and drag inside the shape without removing your finger from the mouse.Refer image C.

( 3. ) Using PUCKER tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 3 positions.Final image:

Pucker tool can be used to shrink the areas. One beautiful thing about this tool that the shape which is being modified using this tool can be alligned easily. You can understand better when you use this tool by Dragging in different direction. It is little difficult to explain elaborately about various styles that can be created using Pucker tool, but i will write about the basics of this tool.Let us see various positions of using the tool. First open a new document of any size. Use the shape tool and select the star shape.
(a.) Pucker tool by clicking in the corners of the shape : Click ON the shape outline  as shown in the image below (click where the stars are placed) and drag in the downward directions as seen in the image. When both the corners are modified, it will look like a petal. You can use the warp tool to sharpen the pointy edge.Refer image A.
(b.)Pucker tool by clicking inside the shape : Click inside the shape as shown in the image below (click where the star is placed). You can just press once or keep pressing till the shape shrinks according to your preferance. You can also drag(after clicking, without removing your finger from the mouse) towards inside to get elongated shapes as seen in the FINAL IMAGE. The movement of the mouse is quiet fast , so be careful in moving in proper directions.. Refer image B.
(c.) Pucker tool by clicking inside the shape and dragging towards outside: Click inside the shape as shown in the image below (click where the star is placed) and drag towards outside without removing your finger from the mouse. This position gives an effect which is similar to the Warp tool. Refer image C.

( 4. ) Using BLOAT tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 3 positions.Final image:

Bloat Tool is opposite to Pucker tool. This tool, expands the area where clicked. I used the same star shape for demonstration.

(a.) Bloat tool by clicking on the TIP of the shape : Click ON the shape outline at the pointy tip as shown in the image below (click where the star is placed). Keep holding the mouse without removing the finger. The more you hold, the more the area will expand. Since it is a pointy edge, you get a Balloon look.Refer image A.
(b.) Bloat tool by clicking in the IINTERSECTIONS of the shape : Click ON the shape outline at the intersection point as shown in the image below (click where the star is placed). ((Clicking exactly at that point will enable the bloat tool to be placed partially inside and partially outside. That is why semi-circle cut is made to the shape. You can move front and back slightly to get the desires bloat size as the BLOAT TOOL size can not be changed.))Keep holding the mouse without removing the finger. The more you hold, the more the area will expand.Refer image B.
(c.) Bloat tool by clicking outside and dragging towards inside: Click outside the shape (NOTE: In the image, the star is placed on the intersection. It is WRONG. Click below the shown area, that is  outside the shape and not on the shape.)and drag inside the shape without removing your finger from the mouse.Refer image C.

( 5. ) Using SCALLOP tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 2 positions.Final image:

Scallop Tool is used to give curvy style.. This tool, shrinks the area where clicked. I used a different shape, that is a rectangle for this demonstration.
(a.) Scallop tool by clicking outside and dragging towards inside: Click outside as seen in the image and drag towards inside the shape.Refer image A.
(b.) Scallop tool by clicking outside and dragging towards a particular direction: Click outside the shape and drag in a straight /horizontal direction, that is left or right and not in a crossward direction.Shape it without removing your finger from the mouse.Refer image B.

( 6. ) Using CRYSTAL tool by clicking and dragging in various positions:
The final image shown here is made by the combination of below 2 positions.Final image:

(a.) Crystal tool by clicking inside and dragging towards outside : Click inside the shape and gdrag towards outside as seen in the image. You will have a crustal effect. it is a very simple tool.Refer image A.
(b.) Crystal tool by clicking outside and dragging towards inside: Click outside as seen in the image and drag towards inside the shape.Refer image B.

( 7. ) Using WRINKLE tool by clicking and dragging in various positions: The purpose of the wrinkle tool is to just give curvy look for the edges. It works only on edges. You might not see its effect when clicked inside/outside the shape and dragged. Click on the outerline of the shape/stroke and do not remove your hand from the mouse and drag the cursor AROUND the shape. Once the curves are applied to the required area, remove the finger from the mouse.