The FIRST thing you should do when a match starts is LOOK AT THE LEVEL OF THE PLAYER YOU ARE FACING!!!!!!!! This can save you some headaches later, and gives a good warning of their skill level. As a bonus, Many experienced players will choose to keep a highly damaged character in for the last few points of damage. They win sometimes because the opponent continues to use intercepts. ( This does not mean you should stop useing intercepts. Just avoid them when possible. Only use them if your opponent is backed into a corner and has no energy left, or it seems very unlikely he can win even with plenty of health. THIS IS MORE IMPortant when considering if someone will switch then the health of a character. Bottom line is: How lucky do you feel Today? :/
SECOND.: LOOK AT THE CHARACTERS ATTACKS ABLITILY AND ITEM!!!!!!!!! It is amazing how many people lose matches because they think they know a character and get taken by surprise when an attack is faster then the one they use, or an item effect screws them over. Keeping track of a characters basic ability saves headaches too. Especially against characters that are immune to stuns, interupts, or poison and burn effects.
THIRD AND MOST IMPORTANT: DONT GIVE UP!!!!!!!!!!! Many attacks have a miss percentage. This is something many players forget, and if you stick with it the game can surprise you and give you a come from behind win. THis is especially true if your last character has some way to stun the opponents character.