Well, first off, as to local "chain" print suppliers here in the US, Costco has from what I see the best reputation, and if you have one nearby, you can upload a pic online and order it and then pick it up the same day.
of course there are also numerous online print providers, I can't give you a specific recommendation, but others will chime in. One outfit, AdoramaPix, has an excellent customer service rep who shows up here, Helen Oster.
As to how to process for printing, well, I'd say it's up to you, there are some "variables" to consider, for instance, how much skill, confidence, "preparedness" do you have in your images and in your post-processing? Do you have a "color-managed workflow" and a good monitor for displaying your images and your work? If all this is a "strange" language to you, well, I'd take some time to "read up", there are a couple "stickies" in this sub-forum dealing with color management and color "problems", check them out...
As to the actual process of preparing for prints, well, the "color-managed workflow" would have you processing in "proper" color-managed software and then you can download "profiles" from your print provider that matches their printer/paper/ink use and then using that profile in your software you can "Soft Proof, "eyeball" and make little tweaks to your taste, then send the high quality file in. You should specify to your provider, "no automatic color correction"!
If, though, you are new to this whole "color-managed workflow" thing, well, my advice would be to start with a good recommended lab and do a bit at a time, get some small prints both with and without the "color correction" turned on, view them in good light, comparing them to what you see on-screen, and decide how to proceed from there!
Prints can in the beginning be a "challenge", but they can be worth it, especially once you make the "leap" and get some nice big prints that are suitable for framing and hanging on the walls