I have experimented in the past very extensively with sigils before discovering a way to use this sigilization method ( https://www.youtube.com/watch?v=lQFenJSs7uw ) very powerfully.
Use the technique like described in the video. Make your sigil, concentrate your intention/desire into it, then immediately carry out the intention with the full convinction after the sigil is made that you can not do anything else. Every thought and action is to be 100% concentrated on manifesting through the magickal triangle of causality (will, desire, imagination). If your attention wanders at all for a moment, immediately bring it back to the task at hand, and keep doing what you need to in order to accomplish what you set out to do. Flexing the will is so easy, it's just making the choice to keep going everytime you feel the momentum of your desire faltering.
Start with stuff you can "easily" do. Caste your sigil, finish the task, and acknowledge the sigil worked and feel as much excitement or other emotions as possible at it working and concentrate them into the sigil.
Initially you'll be doing it for rather mundane stuff. Maybe, if your will is very weak, just reading through a single page in a book or just getting up from bed promptly in the morning or making breakfast.
Each time you caste sigils for mundane shit like this and accomplish it, feel it worked, and caste it again for something else it will be more powerful each time.
If you fuck up once, you have to start over with a new sigil. If you want, you may add a little to the initial sigil with each new thing you do.
In a matter of only hours if you are a pro, you will go from accomplishing basic shit with the sigil, to having concentrated so much power into it that you can achieve superhuman feats. You may use it with thoughtforming, meditation, etc. You may link it to other sigils and in so doing invoke the immensely concentrated power in it to cause it to work with another sigil programmed differently.
Something similar to this I learned about a few days ago from a very accomplished adept is a similar practice with what is called a commitment stick. You add a notch to it for each thing you accomplish with it and if you fail, the stick is worthless. It's a big responsibility to have one of these, especially if it was given to you by someone else, as you don't want to be the one that fucks up and causes it to lose all the intensely concentrated power in it.
If you are extra hardcore, you will punish yourself for failure, by taking some of your blood and spilling it upon the sigil (or stick) and then demanding the universe to challenge you to exercise your will with even more intensity; then you will embrace whatever tasks you are burdened with full of zeal or suffer immensely (either your zeal or your suffering, either one, will purify you; do not numb any of the pain at all, experience the whole ordeal vividly). If you do this purification method, the sigil can be re-used, without losing as much power.
Depending on how good you are with this shit, you could go from something like getting your bed made and your room clean, to exercising psychokinetic powers to drag heavy furniture across your room in a few hours using a sigil like this. It must be understood though that when you are using this technique, the sigil gains its own momentum that takes effect automatically when it is invoked. By this I mean you will seem to be involuntarily carried away by its force towards your goal. It's like how if you always burned a certain form of incense and then immediately went into a meditation in which you go to a specific place you've created in the astral, eventually merely burning the incense will take you there automatically and effortlessly. The sigil is going to power up your will automatically as it gains its own momentum/force from you repeatedly filling it and concentrating it with your emotions.
What is this really useful for? Is there something you're trying to do but you seem to be up against a wall and it's just not working out? Create a sigil like this, do things you know you can do, repeatedly charging it until you feel it has been intensely charged through multiple successful tasks accomplished with the sigil. Then use it again for the really hard task / attainment / goal you want to accomplish. It should help you breakthrough that seemingly impossible barrier with incredible force.
You may also create multiple sigils that are more narrow in their focus and keep charging them like this. One can be a sigil just for studies for example, another just for meditations, another just for exercise/physical cultivation, and you can use each one only for the proper use or you can use conversion sigils to take the energy from one sigil and connect or transfer it to another. You can also make multiple sigils for the exact same shit, so you might make say 3 sigils just for one specific meditation, and alternate between them; that way if one time you eventually are met with failure you've got two back ups handy if you really need them.