Not really. To be honest, it's a pretty shitty system. My best tip is not to bother with a monster medic - they're shitty and innefficient. Train both Noel and Serah up with it bit by bit and have them do the healing work. Sentinels and the Delta Attack paradigm (Comm, Rav, Sen) are life saver paradigm in tough battles, which makes having one of your partners being a sentinel absolutely essential. Outside of that, go with personal choice and experience. Try not to waste your monster boosting items before testing the water with one of your monsters, and make sure that their Feral Link ability is going to be useful (for example, one of mine was a Ravager which used the ability "Friendly Fire", which basically causes damage to the enemy, and then heals your party with the damage dealt, essential for interrupting/delaying an enemy's major move and getting emergency health boosty).
if you want a good sentinel get a pulsework gladiator or a silver chocobo (which you can use in the chocobo's races in serendipity). if you want a good commando try getting Chichou, he is the most op monster in the game.