How can I light up my backyard? ?

Likeother people suggested ... go with the solar option.

I have solar yard lights that have detachable stakes. Perfect for placing on a post that has been drilled to accommodate the light unit. Also, you can purchase solar lights that are specifically made for posts. 

Some solar lights have a lantern design, made for hanging. You can push Sheppard's hooks into the ground and hang the solar lights from the Sheppard's hooks or create your own stake or post with a hanging bracket.

The best selection in stores for solar lights is in the spring, however, you can buy them on line.

You can get some great ideas on solar lighting on Pinterest.com

Somewhere I saw Tiki Torches but they had Solar Lights on top - they wouldn't put out much light but they'd give a cool aesthetic for a reasonable price.

how about with a ride on lawn mower and some sweat ..and some flood lights .. After all 1acre is a big back yard .

Addison has a great answer:  look into solar lighting. It may be expensive to buy initially, but you will never need to worry about your electric bill after it's in. You might also want to check windmills--for wind powered electric--in your yard. If you have that much land, there's no reason the investment would not pay off. 

Go solar power, use solar powered lights that charge during the day and light up at night. That will save you from running expensive underground conduit to supply power to lights. They make all types of solar powered lighting.

Plant a tree? Strong flood lights suck a lot of electricity so your electrical bill will be higher. Who cares if they are level? ONLY YOU (for some reason).  There are just some things you don't do...because it is not practical...and just too expensive.  

. You could always make bonfires and you have heat, light and smoke to drive the mosquitoes away...and you can smoke fish & bear meat or what have you.

I, too, have had solar lights fail on me after what seems like too short a time.  the problem is, I think, the batteries they include ... they're recharged every day, but will amass over 700 charge/discharge cycles in two years ... that's probably beyond the design limits for fairly cheap ones.  Wired LEDs are quite bright and one fixture covers quite a bit of area, but you have to run the 110v wiring to where you want them installed [corners of the house are typical locations].  That's a fairly ordinary DIY task and well within your ability to learn and do safely.  the most onerous part is running the required wiring through the attic -- I connected mine inside the nearest ceiling light fixture and keep the exterior light fixture under the overhang of the eaves [to protect from weather].  Yup, I've been doing one added fixture every other year or so, starting with the most important ones.  It is also possible for a DIY guy to run an underground line inside pvc conduit [I use UG cable inside the conduit -- the conduit is to protect the cable from the stray shovel, not from water -- UG cable with no joins does that just fine] to a post or outbuilding in the yard.  That's a fair bit of digging work unless you rent or borrow a small trencher.  -- GL  -- grampa  {I've maybe the fifth or fourth part of one acre out back, but installed a light in the front as well because the builder didn't do it when the house was built.}

I'd say about a full acre of land

YOU don't have a yard. If you did, you would KNOW the size.

Im not really looking for string lights or a mobile flood light

If you think that is even a poor option, you don't have anywhere near the property you claim to believe you have.

I was also thinking the DIY way

asking this question rules that out.

Define "looks good". It is probable that our definitions differ.

Rather than jumping to the solution, figure out what you like. Then we can help find alternate ways of getting to that.

Another option grows the lighting. You might not be able to afford all the lights at one time, but how about installing 1 or 2 each month? The first one will be expensive as the power supply, cabling and design for all of them should be installed to start, but after the first one, additions *should* be easier. Devise a proper plan and stick to that plan. Changes to the plan may increase cost... Use light fixtures and connections designed for outdoor, wet, use.

And since you are asking, this is probably best for a professional to do - Improper installation can result in electrical shorts, damage to the power infrastructure of your home, fire, even death - especially because of the weatherproofing requirement (for example, using a properly installed GFCI-protected circuit).

Tiki torches      .