how do I tighten or change the drivers side wiper arm?

 

It's pretty self explanatory with the nut on top.

I'm gonna assume the linkage is sloppy since you want to tighten it. You have to pull both wiper arms, remove the plastic cowl, then replace both linkages under there. Don't waste your time by only replacing one.

 

those linkages wear out they use a plastic bushing that eventually wears out.

The parts you want are:

Rod A 76540-S10-003
Rod B 76550-S10-003

They are $14 a piece from hondaautomotiveparts.com there might be a better site but shipping to the lower 48 is about $10 from that site so you're looking at a $40 job. Trust me it's worth it I despised having to time my wipers to stop at the right part.

It would also be wise to go ahead and put some sheet metal over the outside air hole. If it hasn't done it yet it will eventually leak under your passenger side dash without doing a fix like this

 

I have replaced a couple of these, get replacement windshield cowl clips off ebay along with the wiper arm.