Looks like you overbet the flop and potted the turn? I go for $5 on the flop and 3/4 pot on the turn. I doubt he's calling $15 instead of $20 here though, so you probably did the best you could. Remember, even a half-pot bet on the turn will deny pot odds to a flush draw, assuming he has no other outs and you won't call a bet if his flush hits. To be safe though, I usually bet 2/3 to 3/4 pot in case he has a pair (and two more outs).