Some crucial points I learned while baking my own weed cookies... some were already mentioned but maybe this collection will help you.
- Decarb your stuff because the THC is ineffective without being heated. Means you tear the weed to pieces, put it on a baking plate and bake it at 110-120C for 1/2-1 hour.
- Use fat in whatever edible because THC isn't soluble in water.
- For making cannabutter, put water and butter to boil with the weed for about 2 hours, then sift out the weed and allow to cool overnight. Now you can use the hard butter from the surface for your edibles of choice. This way you get rid of the grassy texture and taste, and even leaves or non-quality weed can be taken advantage of.
- When you bake, don't do it over 160-180C, rather a little lower, to save as much THC as possible.
- I still don't know if all those processes make sense in one recipe as I do it all - decarbing, then cannabutter, then bake my cookies. Maybe if you add fat and slightly heat it it's completely enough? I was satisfied though with the results and think I really use the THC content effectively
- When you choose the strains to produce edibles think about the smell - very smelly strains as for example Power Plant or Diesel can destroy your roommates' mood and your neighbours' tolerance
- Usually I buy some different strains of weed, test them by smoking, and then I take those that were least special for the edibles.
- Before I offer my cookies to someone else, I usually test them so that I can be sure of the dosage.
- The effect depends on the circumstances though. Your weight and your metabolism is one thing. Most decisive imo is if they are eaten before or after meals. For me, the effect before meals takes about 45-75minutes to be noticed and feels stronger per edible. After meals it can take 90min up to 150min and the effect is weaker imo.
- with all those numbers calculated the high is quite predictable, well, as predictable as highs are
- Edibles are a good and discreet way to enjoy non-smoking events... train journeys, concerts, museums & exhibitions...
- my recipe is usually: 1,6g of good weed, decarbed, and made to cannabutter with about 50g of butter. Next day, take the butter, about the double amount of flour and an egg and make a shortcrust dough. Then add either sugar and spices (cinnamon, vanilla, ground cloves, cardamom...) or a little salt and for example provence herbs or cheese. I have not noticed effect differences between sweet and salty cookies. This should make about 16 cookies (divide the dough in halfs and do so until you get 1/16 pieces) so every single one is equivalent to 0,1g weed. Bake at 160C for about 20min. Depending on the quality and your needs, 1-4 will do

Those can be stored for about 3 months or put into the freezer, tightly wrapped. Don't forget to keep them away from those who don't know, even better mark them - I like green sugar sprinkles
EDIT: Funny adventure when I baked on a morning recently: Don't underestimate what's left in the water after removing the cannabutter! Thought I'll have a little tea made of the water (original amount had been 2,4g weed) and did not expect any effect... and was early to the party

At least the effect of 3-4 cookies I guess...
"God's herb, puts you in the moment. Smoke a little and let it do its thing!" (H. Diltz)