How to make deep work easy

Start small. You can try concentrating on your task for 15mins,then taking a 5min break, then again 15 or 20 mins, after that again a 5mins break and so on. I have trouble focusing but I have managed to stay in focus for 30mins. You just built to it. Practice again and again and it will eventually start being easier.
If the task seems to be overwhelming, you can try "breaking" it into smaller tasks and work like this. Make smaller goals and by achieving them you will feel better and will wanna focus more.
You can also check the things that are bothering you as well. Maybe the reason why you cannot focus easily is your environment. Maybe the room is too cold or too hot, too noisy, too messy etc. By creating a good environment (based on your task) chances are you will be able to focus easier and longer.

I think blocking all distractions really is key to making deep work easier. Like putting your phone in flight mode and placing it in another room. Another idea could be to try to make the deep work s nice as it can be. Sitting in a comfortable chair, putting on a comfortable sweater and bringing a big cup of your favorite tea. I hope this helps!