I've noticed after doing a good few filters on new hands and old that I tend to play my A game pretty solid for the first few k hands of any session. (generally)

There is run good in there too , but after a while I start playing more and more less logical, I'm ample rolled for my the limit im playing, I have a positive winrate, yet I know that I'm thinking better at the start.

It could be simply mental tiredness, and robotic moves if playing fast variants of holdem 4 tables,

Anyone got tips on how they keep themselves playing theyre A game?

My general strategy is to try my best to not do stupid things. It works sometimes.

do exercise, sleep well, eat healthy to help feel good when session starts

During sessions, take some small mini breaks occasionally. Even MTT players who grind 12hrs in a row some days have 5min breaks every hour.

I play poker for a living and have done so for a very long time. Staying focused and playing kick ass A+ poker takes hard work and focus. It is a lot like being an athlete in terms of progress. If you are trying to get into tip top shape you DO NOT go into the gym your first day and work out like a machine for 2hrs +. Its just not possible. The same holds true for playing poker. Being able to focus and play at your best may only last for 45 minutes. But the good news is you can work out your brain just like your muscles and be able to focus for longer and longer periods of time. When you feel your a game falling off - shut down give yourself a rest and when you are rested re start.

I remember after black friday I had to start playing live poker again. I would be fried after 4 hours. I would be like WTF why am I so shot. It took some time but I slowly got my session lengths longer and longer. To the point where I could play kick ass poker for 10hrs with out much effort.

My post was lazy. This one:

is much, much better.

This is my favorite part, particularly because I love analogies.

Now where's that damn analogy containment thread I meant to start?

If you want to play your A game a greater percentage of the time, then when you notice you're not playing it, stop playing

This. Everyone has different lengths of time for how long they can maintain concentration. I've got worse and worse in recent years (my attention span is ridiculously short these days), but try to take at least 5 minutes off at least once an hour. One problem I have, though, is that when I'm tilted I'll think something stupid like "I won't take my break until I've won back half a buy-in"... and before I know it I've lost another stack. It's extremely important, I think, to give your brain a break every 50-55 minutes or so, and this break can also help prevent tilt building up.
In my experience, once the session graph starts going down, it usually keeps doing so, so it's often best to quit as soon as you've reached a threshold. (Some training sites/coaches even insist their students have a stop-loss of 2 buy-ins. It's very hard for many players to maintain their A-game after a couple of big losses.) It all comes down to discipline. You have to know when to take a break or quit, and then you have to stick with that plan. If you know your brain only works properly for an hour, then stop after an hour. Don't push your brain/body past its limit.

Pre BF I stuck in 8 hours straight a day for ages clearning the hands in a staking agreement wasnt playing my A+ game Id call it a A-/B+ and did well, now Im 32, two daughters and stressful last few years. (lost a son, kicked a drug habit. gained way to much weight (which starting this Friday Im attacking like I would a leak in poker) also gained two girls, but the second one was born two months early, and was in the same place as where we lost our son

(he was 23 weeks and a few days, legally at 24 weeks they do everything to save them EVERYTHING) he was 2 days short of 24 weeks, so instead of a rescue operation my wife gave birth to him, they put a heart monitior on him and we all stood there in waiting in enterinty for the fast at the start to slow slow slow slow slower and distant thud and nothing. No BEEEEEEEEP like in the films. Just watched him die. No that my internet friends was fuked up in a big way. Found a place for him in my heart and live and see him in the two sisters. But will always be a factor in my concintration.

Sad story FNH. Good luck moving forward.

Jeez man, that story is upsetting. It's "real life ****" like that that reminds me how poker is just a stupid game that I take way too seriously. Poker can definitely be stressful, so you should do whatever you can to reduce/relieve that stress, but being at peace in your home life is so much more important. I can't focus on poker if I have even minor distractions, hence my low volume, and usually very short sessions.

Multiple sessions a day. Going back to the real worlds can be helpful. Maybe like 3 hrs, then run some errands, 2 hrs, then eat something, then 1 hour. Something like that.

Squid Face nailed it.

However, the hardest part as Tommy Angelo pointed out years ago isn't knowing when you aren't playing you aren't playing your "A" game. It is about standing up from the computer (or table).