if you get to like 5-6 hours into your day and are just like, “god, why am I so fucking tired today?” go check if you took your meds. (I highly recommend getting a day of the week style pill counter so it’s easy to verify if you did.) Damn near guarantee you forgot. 
The effect has been pretty profound.
@Vixanic sorry for the maaassive wall of text though it probably isn't that hard to get through if you're just starting on Elvanse, lol.
One final recommendation: I found it difficult to get enough calories, maintain a balanced diet and remember to eat in general while taking Elvanse. Since as mentioned this kinda fucked up my body, I realised I needed a serious solution for this and did actually find one.
Huel works really well for me, it's quick, convenient and very easy to keep track of for calorie/portion control purposes. I've personally seen a lot of health benefits from having this on hand alongside my ADHD medication. I'm not affiliated with the company in any way. (I can pass on a discount/referral code but swear that's not why I recommend it.)
I also got some blood tests through private referral to ensure there weren't nutritional factors in my inability to concentrate etc. and recommend that if you fall into the trap of forgetting to eat or something. (Did have a couple deficiencies for a bit and addressing them did help.)