Formerly, I never needed a kitchen timer. I hadn't even bothered to learn how to use the timer function on my microwave. Thank Goddess it's there, though, because I now need to remind myself that I put water on to boil lest I set the house on fire. I'm really glad that my mom taught me never to leave anything flammable near the stove, because I have gone away and left the burner on quite a few times now. Get in the habit while you're young and it can save your life someday!
In addition to using a timer for every stage of cooking, I have utilized post-it notes for many things. I have a post-it above my computer with my phone number and zip code, since I can not always remember these off the top of my head. (I used to keep lots of people's numbers and zip codes in my head. Those were the good old days.)
If I have an appointment, which I mark down in two different calendars, a planner and a wall calendar, I make a post-it the day (or two) before and put it on my mirror so I remember to set my alarm and I remember later what the alarm was set for. My husband also helps to remind me to put the note on the mirror.
When I make an appointment, I've learned the hard way to repeat everything back to the person so I know I've written it down correctly. I once failed to show up because I wrote something different from what I was hearing.
I put my handicapped placard on the door handle so I'll see it on my way out. Other important items can go next to my purse and keys. I have a consistent place for those so I'm not searching the whole house at the last minute. If there are additional items I must remember I put a post-it on my door so I'll see it before I leave. I also make a list of questions or concerns to mention to the doc so I don't forget them.
I aim to get there fifteen minutes early so if I do forget something I have allowed extra time to look for it or come back for it. I've also learned not to get involved online or in a book so I won't lose track of time.
I've posted the monthly bills on the fridge so I don't forget any. I keep any new or one-time bills in my planner so I remember to send a check.
Thank Goddess for Tivo because I can't even focus on the weather through one whole broadcast so when I go off on a mental tangent I can re-wind and catch it again. I've had to re-wind several times on some nights.
I've learned to swallow my pride and ask people to repeat what they just said if I was absorbed in something else when they started speaking.
When I can't think of the word I want I've learned to write or talk around it or simply describe an object until the other person supplies the missing word.
I haven't stopped wishing I had my old brain back, but I'm living with the brain I do have much better now. It's taken time to learn to do things in a new way and create systems for myself.