Hi,
Villain is unknown, I think standard option is to flat pre flop. 3betting leads us probably to more tough spots when we have no reads from our opponent and QJ against 2.5x co is good enough to flat.
Postflop: With this hand we have like 1 street of value on the flop we don't need that much protection since we hold one 
so I decided to go for a ch/c on the flop. Villain checks back and I put him on 88, 99, Tx occasionally air or some AQ, KQ or Jx may check back. Turn I think we should bet for value. Getting raised on turn is strange since I expect villain to be betting all his sets and AJ, KJ types of hands on the flop. As played calling turn and folding the river - I just feel most of the time we see here AJ or KJ.
I feel it's a mistake to call turn with the intention to fold into a brick river. On the other hand I feel villain might be just randomly raising some Ax on the turn and then give up the river which would make sense for us to call turn - fold the river. We still may have even TT in our range on the river which might go for a CR on the flop so folding QJ isn't even the top of our range OTR imo.
Poker Stars, $0.25/$0.50 No Limit Hold'em Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.
SB: $51.21 (102.4 bb)
Hero (BB): $105.79 (211.6 bb)
UTG: $56.75 (113.5 bb)
MP: $141.90 (283.8 bb)
CO: $59.01 (118 bb)
BTN: $49.50 (99 bb)
Preflop: Hero is BB with Q
J
2 folds, CO raises to $1.25, 2 folds, Hero raises to $4.50, CO calls $3.25
Flop: ($9.25) T 7 J
(2 players)
Hero checks, CO checks
Turn: ($9.25) J (2 players)
Hero bets $5, CO raises to $15, Hero calls $10
River: ($39.25) 5
(2 players)
Hero checks, CO bets $39.51 and is all-in, Hero folds
Results:
Spoiler
$39.25 pot ($1.77 rake)
Final Board: T 7 J J 5
Hero mucked Q J and lost (-$19.50 net)
CO mucked and won $37.48 ($17.98 net)