Keep a towel with you. After you're finished with bench press, wipe down the bar so that the person after you can use it. This applies to any other exercise that gets your sweat on the equipment you were using.
Re-rack whatever weights you were using after you're finished with them. Put them back the way you found them. Don't drop your weights on the floor unless they are rubberized or there's a mat there. Don't keep a bunch of equipment occupied.
Rearrange your workout so that it's less inconvenient for others. Or if you must have it all, then go to the gym at a time when it's mostly empty.