buy and sell

HI guys/gals what the general consensus on buying and selling I never seem to get it right bought in at 12c fell to 6c didn't buy more .The price went back up to 17c bought in then bought in at 25 twice was thinking of getting out at 37 decided not to .My question is it worth selling out at 37 and say getting back in at 34 and buying more shares at that price.(any stock) or sit and play long game . my track record is terrible was in voc up to $9 and sold out at 4 so badly need of help lol plus being an oap doesn't help my finances when i lose