The biggest thing is making sure the bow fits you and that it's tuned correctly. Fiberoptic sights aren't a must, but they are nice. Same thing with drop away rests and carbon arrows.My father still shoots old XX75 Alum's out of his old Golden Eagle with metal pin sights and a simple prong style rest. It still kills deer. The key is making sure it all works together. Take your bow to the local pro-shop and have him check it over for saftey issues, make sure it fits you, have him square it up and see if he can give you some ideas for accessories for your specific bow.

Now let's say you made sure the bow fits and all that jazz. A few accessories I would recommend right off the bat for an older bow would be limb silencers (Limbsavers), string leaches, and a stabilizer. These really are good things to add for any bow, but especially on older noisier bows. Also, to help improve your accuracy, add a kisser button and a peep sight. This will help with consistency, increasing accuracy.

After that, practice practice practice. Practice from every concievable position you think you'll be shooting from in a hunt. If you think you're going to sit on a bucket flipped upside down - practice from shooting on a bucket. From a chair - practice from a chair, etc, etc, etc. Also practice on making your first shot count. Focus on making that first shot of every group or session perfect. Last is concentrate on keeping a consistent form. Have someone take pictures of you from several angles while practicing and post them up here. We have some awesome shooters on here who can give you a ton of good pointers for improving your form and accuracy.