Maintaining your table is really important.  I've worked with a lot of great servers that sell themselves short by not pre-bussing their tables or asking their tables how everything is going.  It's the combination of pre-bussing and check-backs that show your tables you really care about them.  It also helps turn your tables faster.
 
    Pre-bussing basically means removing everything from the table that is no long being used.  Extra silverware, empty glasses, and unnecessary plates should be removed as quickly as possible to make your tables feel special and attended to.  Don't expect your busser to jump in and do this for you.  You have a better relationship with the table and it's easier for you to get in there without interrupting them.  Another bonus, your bussers will love you since there won't be much left on the table to clean once the table gets up, and they'll probably clean your table before another servers since it's only going to take them a couple of minutes.
    
    The best and most important times to check on your tables is either right when they get their food, to which you say, "did everyone get what they ordered and is there anything else I can get you right now", or right after they take their first bite, to which you say, "how is everything?"  There's nothing worse than when everything comes out perfect except one person didn't get that side of ranch they wanted, and you're nowhere to be found.  

    Another great trick is to anticipate their needs and bring them something they didn't ask for, but that you think they might like or need.  For example, "here's some extra napkins and some hot sauce that's really good on that wrap, can I get you guys anything else?"  People LOVE this.