Post buy in period play??

[SmilinMark21]

Dear all,

I have been learning and playing pot limit hold em over the last 2/3 months, i have over the last 4/5 times built up a fairly tight aggresive style of play that has meant that i can take value on the hands i am strong (this is a cheap £5 rebuy game, so many limpers).

So recently i have been building up a decent sized stack before the cut off, but after the cut off as the play style changes i can steal a few but i find that many hands are bet first take it with all bets being of the pot, anything less is usually called

of course i continue to play tight but i find that with the blinds raising i am out or when i have raised have been unfortunate with a caller, what do you advise as to play strategy here?

thank you....

Mark