Older kids can be tricky
Not all people, especially older kids, like to be in photos. It can definitely be a challenge getting everyone on board with the idea, for sure. Luckily, older kids usually have a better understanding that photos are something that is important to mom, so you do them. This still doesn't make it fun or easy for them.
Give them something to do
I have found that when older kids feel like they have a purpose and are not just standing there feeling awkward, they enjoy the experience much much more. I always try to keep my "how are people feeling" radar on, during a session and do my best to ease the tension and make the experience more comfortable. This might mean a simple game of running under the blanket.
Teenagers might appreciate really any direction given. Being the photographer is all about guiding each person through the session. No one likes to feel like they are not sure what to do or where to be. Being in photos comes naturally for some, but not everyone. It is good to keep this in mind and be ready to give some simple directions.
Don't be too pushy
If you ask an older kid to give their mom a kiss on the cheek and they don't want to, don't push it. Have a quick backup plan so your session can continue to run smoothly.
I know everyone is different and thrives on different types of attention, but as a general rule, I would recommend not being the photographer that is pushy and in their face. Older kids usually like joking around and that can sometimes be an ice breaker, but don't push it. Older kids need to be allowed to be themselves.
Let them be themselves
Like I have mentioned, when I am taking photographs I am guiding my clients through the session and giving praise. A photo session can be a walk in the park for some or an awkward challenge for others. Either way, humans like to be told when they are doing the right thing. It gives us confidence and encourages us to move forward. So, definitely, photographers need to give some guidance. However, we also need to let them be themselves. Older kids especially will appreciate this gesture.
I hope this has been helpful. Have fun photographing life!