1. The good strategy is to earn TE and Pots to buy MLB monsters instantly. I think Pale monster priced now at 10-15 with Max level, MLB stray cat is now priced to 8-10 TE since that monster is done by completing artifacts from the quest. Other 4* like King Mandragora is very winnable too because of its big amount of hit points.
2. Keep all strong monsters as you can.
3. My best recommendation is to have more stray cats and king mandragora maxed to your team. Or maybe lizardman and salamander at least in the start. My other recommendation is to try 26-5 for easy enhancer. And finally, don't let your strong monster to be albumed or lend by other player or else you will be screwed.
4. My suggestion is to join event for more monsters to get.