what have you been playing? the best way to grow it for most people is playing cash tables and its the safest way to go. i prefer sit and goes and tournaments for the thrill of playing to be number 1 i suppose...my
bankroll is always taking huge swings and i play higher limits than i should. you are supposed to play limits where you can afford to run bad and wont be so emotionally drained from any single hand or tournament. this means you likely arent turning 475 into 1 grand tomorrow but its safe..i think you are safe playing .25/50 cash table but others may disagree im not sure. at least .25/.50 just find something u are comfortable playing and feel up to par and grind away. find things to accomplish like 1k
hands or something(this is what i do to get through grinding) helps to set small goals to reach.
remember the most important thing in building a bankroll is patience..I think most people agree. you can have all the skill in the world and even run really well for a while but without patience and knowing when to take breaks and stop playing u will have 0 before you know it. i would think if you lose 5% of your bankroll in a day or long session you may want to take a good 3 hour break or longer. what i do when i start getting overly tired but feel like im running well or trying to play catch up is give myself some limit i can lose then i turn everything off and go to sleep and wont allow myself to play again until i get 8 hours. if you take a 3 hour nap and wake up thinking u r well rested its just as bad as playing too long of a session...for me anyway.
last bit of advice i forgot to add is ive read from some big name pro(forgot who) that he would always force himself to quit if he lost half of what he had previously won that day. probably a good thing to do. there is always tomorrow and a lot of these poker players are soo good now that they will attack a player who is showing weakness. when i see a player starting to tilt from a beat or just seems overly tired i will do everything i can to get into a big pot with him/her.