1st, I'd remove the optical drive and install one of the many optical drive/HDD install brackets that allows you the ability to install two internal HDs into your machine with the sacrifice of your optical drive. Ask yourself this question, how often do you actually use your optical drive in this day in age anyway. (With just about every software title offered via download and pretty much all media available via streaming it's probably not that often.)
2nd, install the new drive into the bracket that just replaced your optical drive or flip flop the locations of the old and new drives. Honestly, it really doesn't matter because they both use the SATA bus and are accessed at the same speed from either location. Now put the bottom cover back on and the install phase is done. (This is a pretty easy install with few tools required and specific instructions are available all over the internet.)
3rd, Boot your machine. Your Mac should see the original drive as the startup volume and boot without any issue just like before. If it doesn't, boot holding the "option" key, this allows you to choose the proper boot volume.
4th, Once booted to your old drive open Disk Utility. In the left column select the new drive and then click the "partition" tab. Next, click the drop down on the left and choose, "1 partition", then click "partition" and confirm the step to partition and format the new volume as needed to proceed. Leave the name of your new volume as "Untitled", as it will get renamed during the cloning phase later.
5th, Now that the new drive is partitioned and formatted, click on the original hard drive, not it's volume name like "Macintosh HD" or whatever else it's named but rather the actual hard drive just above the indented title "Macintosh HD". After that's selected click the "Restore" tab. Once in the Restore panel the "Source" field will be auto-filled with the old hard drive. Leave it that way!! Doing so is very important! You will see an empty filed labeled, "Destination". From the list of volumes on the left, click and drag the volume titled "Untitled" into the empty destination field. Now click the "Restore" button in the lower right corner and then confirm that you understand that any and all data on the untitled volume with be lost. (It's empty at this point anyway.) After about .5 to 1.5 hours this process will be finished and as a result, you will have an exact clone of your old hard drive including the recovery partition. (Some of the suggested options will leave you without a recovery partition, this is not advised)
Lastly, You now have two identical hard drives... Open "System Preferences" and click on "Startup Disk" and click on the new drive that will have the exact same name. It will be the one not highlighted until you click on it. At this point click restart. Once you're machine is back up you are now booted to your brand new SSD Drive and you should have noticed a much faster boot up sequence. Sometimes the first boot up is a little slower than subsequent restarts but you should defiantly see a good result from the time and money investment you just made. Now that you're booted to you new drive, open "Disk Utility" once again and erase and rename the old drive to use it as extended storage, backups or whatever you want to do with it. In my case I upgraded it to a 1TB standard SATA drive but it's really up to you, as to what you do with this secondary volume. Now you have a portable machine with as much, or more storage than some desktop machines. Note: If you want to put the optical drive to good use you can purchase an inexpensive external USB interface, optical drive enclosure for those rare cases when you do need to access an optical disk of some sort or watch a DVD rather than stream it.