Saving your photos and videos
Use Google Photos? Good news, you don’t have to do a thing since all of your photos and videos are already stored in the cloud. Google offers free unlimited storage of high quality photos (not full resolution), so even if you don’t have Google Photos, you can download the app and let it backup all of your photos to the cloud for free. After that, you can use the Google Photos app on your Android device to see all of your pictures and videos.
Alternatively, if you don't want to use Google Photos, you can transfer photos and videos using the old school drag and drop method. Plug your iOS device into your computer, browse for all of your camera photos and videos, and drag and drop them into your computer.
Once the transfer is complete, connect your Android device to your computer, and drag photos/videos to your Android device. If your Android phone has a microSD slot, just transfer your photos to the microSD card before slotting it into your phone.
Taking your music along
Google lets you transfer up to 50,000 of your songs from your iTunes library to Google Play Music for free.
Plug your iOS device into your computer, browse for music in iTunes, and drag your songs to a folder on your desktop. Once that's done, plug your Android device into your PC, and drag the music folder to your Android device or its microSD card.