Random tips acquired in ~20 years of off-and-on DMing:
Above all else, know your group. No two tables I've ever sat at (as a player or DM) played the game in the same way. I've been around heavy RPers where an entire session can go by without a single die being thrown. I've been in groups that love the puzzle solving aspect of the game - either in surmounting certain challenges or investigating for clues to crack the case. My last table had a very strong video game/tactical board game background and they gravitated heavily towards the thrill of very challenging combat encounters. That's not to say there weren't examples of all 3 elements in each group, only that certain groups gravitate more towards some themes. There's no "right" way to play D&D, only what's right for your specific crew. Try to get a feel for what they enjoy most and tailor your sessions to lean in that direction.
When in doubt, ask them. I conducted a fair amount of campaign business via email in between sessions. Not only does it help you gauge their interests and be a better DM, it can eliminate some of the "busy work" that might bog a session down - like going over crafting rules and some of the other micromanagements.
Encourage one of your players to be a journal keeper. In our group one of the players brought a day planner booklet and jotted down notes from each campaign day. Then, once the campaign has ripened after a while and some seeds you laid in an early adventure are approaching fruition, the players will have an easier time recalling past events if the journal keeper has it written down. Remember, the players will NEVER know your world, your story, your details as well as you do. As the creator and the guy doing most of the work, it is your baby and you can't expect them to recall Charles the Bartender in that town they all visited 8 months ago and that the medallion he wears around his neck looks exactly like the shape of the depression engraved in the block of stone they just discovered in some dark crypt.