Bar tape comes in so many colors and materials that it's hard to recommend anything. Poke around on eBay or Amazon, and find something you like. I use the thicker, softer products, mostly because it feels good, but also because it "hides" the cables, better. Some bar tape has adhesive on the back to help hold it in place, and this can vary, as well. Plenty of discussions about bar tape on the forums; just do a search, or watch some videos. A little time and focus can result in very good tape jobs, especially if you have that dexterity that some people seem to have with "crafty" things, like painting and sewing.

Chain cleaning and lubricating may be the most-often discussed subject on BF. I use motor oil diluted with mineral spirits, at home, but I use commercial products, if I'm not at home and need it. Lots of ways to clean. Some use the "machines" that have brushes and tanks for solvent. They look like they will work, but I just break the chain at the master link, and soak and scrub in mineral spirits. I oil the chain when it's back on the bike, and wipe it with paper towels until they come away pretty clean, and there is no more dripping. I clean the RD, cassette/cogs, and chain rings while the chain is soaking in a Mason jar.

One way to be sure your disc brakes aren't dragging is to remove the caliper and spin the wheel. If it spins more easily, then the brakes probably are dragging, and need to be adjusted. Some brakes have mounting holes that allow for some play when the caliper is installed. Lots of discussions about that process, and YouTube videos to show you good ways to center the caliper on your brake disc. It's not hard, and you can do it with just a couple of tools. Make sure your disc isn't warped, and that it's solidly attached to the wheel.

YouTube and the Park Tool web site can practically turn you into a master bike mechanic, if you have the motivation, a little time, and a little money to spend on tools.