(edited because I'm a gimp and confused this hand for one that had 50/100 blinds - thanks for pointing it out to me (below) Nath)


Preflop you shouldn't just limp. With 4 limpers in the pot and the size of your stack you can easily put in a raise up to about 150 (I would go a bit higher than 3x due to limpers but not so high that it looks fishy). Allowing them to see the flop with weak holdings this cheap is a sure way to lose, especially with a hand like AJo that isn't all that strong and somewhat vulnerable but could still be the best hand at the table for the time being. If you don't get any callers that's fine. Taking it down right here isn't the worst thing in the world.

The postflop minraise is horrible. At this point if you think your hand is best the message to send again is that if you want to play this pot you're commiting more chips to the pot, shortie! If he's drawing at a straight you want to charge him for it. A raise of 100 isn't a tough decision, in fact it's a very easy call. Raising to 400-500 puts him on a really tough decision. If he's drawing at a straight or flush he can't call here since he doesn't have proper odds to continue. If he does call he's making a mistake that ends up as money in your pocket. If he has something like top or second pair he may call anyway not putting you on a jack.

The idea here is to put pressure on your opponent. There was no pressure on him here - his decisions were too easy to make.