Try the shape Builder tool, it lets you precisely combine many shapes into one in a more intuitive way.
To create a shape using the Shape Builder tool, do the following:
- Create the shapes on which you want to apply the Shape Builder tool.
- Using the Selection tool, select the paths that you need to merge to create the shape.
- Select the Shape Builder tool from the Tools panel or press Shift+M. By default, the tool is in merge mode, where you can combine different paths. The pointer in this mode appears as .
- Identify the region that you want to extract or merge.
- To merge paths, drag along the region and release the mouse, the two regions get merged to form a new shape.
Here's a tutorial from Adobe