Allow me to begin by saying I find the above image disturbing on many levels. First off if you're have these sorts of doubts all popping into your noggin while trying to do a spell or ritual, then you are going about things the wrong way. Sorcery requires your undivided attention. You need to reduce the distractions to a bare minimum and this includes the internal chatter that goes on. If your mind is wandering around like this woman's then stop what you are doing and put your tools away and focus on some concentration exercises. These will help you hone your mind to a more straightforward sense of purpose so that your confidence will be strong and the doubts will be next to nil if not totally absent.
The "what am I doing" is extremely disturbing from both an elder and a teacher viewpoint because JuJu is real, people, it is not some made up psychological trick you use to bypass your psychic censor like new age authors want you to believe. Instead it is about harnessing the power of your mind and making contact with the world of spirits who you can employ for your rite's needs. If you don't know what you're doing, stop and either (preferably) get training or hit the books and study on your own or go through some dry practice runs until it seems more natural to you. A sorcerer who does not know what s/he is doing is the most dangerous kind of sorcerer, bar none.
The "wtf is ylang-ylang?" shows that the student has not bothered to study the spell that she chose to work. Know not only the spell/ritual you plan on performing but also the ingredients as well as tools you plan to use. You should know how each item works in the working. You see each herb, root, stone, crystal, tool and so forth has multiple functions and rare is the ingredient that has just one function. However some ingredients only function in certain ways when combined with other select ingredients for specific needs. Further some herbs and roots are twisters meaning they can do good or ill depending on the recipe and desire of the practitioner. Thus know what you are using and how it's being used.
The bottom two questions: "Am I doing this right?" and "Should I start over?" are questions that every Novice has asked themselves at one point or another. I guarantee you even Agrippa had some sort of doubt somewhere in his early career. It's natural. Butterflies in the tummy they call it for actors. It's just self-doubt mixed with a bit of worry. Nothing to fear. To answer the first question, how would you know how it's done right to begin with? Have you seen someone perform the spell or ritual before? If not, then you have nothing to compare yourself with thus stop worrying. As for starting over, well my question is, "Other than delay you, what would that accomplish?"
There was once where I began a Martial ritual and I made an utter mess of things. Oy! I had on one of those annoying Tau robes with the long sleeves that hung way down and I wasn't paying attention and it knocked over a lit candle which caught the damned altar cloth on fire which caused me to jump up and I caught the sleeve of my Tau robe on fire and I had to run and grab the fire extinguisher and ugh. SO YEAH if you blunder the entire thing you can start over as I did. I was going to hold off but I said, "Know what? I waited too damn long for the conditions for this to be right so screw it! I'm going to start over and I'm taking off this damn tau robe and doing the ritual in my undies!" Needless to say I removed the burnt altar cloth as well and told the spirits, "I don't care! The show must go on!" When finished the talisman was highly charged and I think the Seraphim got one helluva kick outta me and my frustration. (Spirits do enjoy seeing us all flustered, you know!)
Finally, "I fucked up" and to that I say, "So what?" It's not the end of the world. Ask any mainstream occultist, author, blogger, & etc, if they ever fucked up. Hell ask any Houngan or Mambo if they ever fucked up and they'll all tell you, yes. At least once. It's NOT the end of the world! Don't lose your shit over it! Okay? Just take a deep breath and relax. The spirits are more forgiving than you realize. Even the Yorbuan Orisha, as snooty as they are, can be forgiving for an error because we all do err. Worse comes to worse, and if you really feel that bad about, just tap on your altar thrice and announce to your spirits that you apologize for fucking up.
Does a judge throw you in prison for mispronouncing his name? No, you apologize, let the matter drop and continue on. Would a senator who likes JD whiskey have you shot if you gave him a bottle of bourbon instead? No, you'd just apologize for your error and carry on. Social faux pas happen and the spirits expect such as well. Just try to be mindful and learn your craft because the older and more experienced you get, the less forgiving the spirits tend to be. Why? Well by then you SHOULD know how to do X and not make amateur mistakes. Right? ;)