With no garage either, I've been living with two 10 X 12 sheds for many years. (When one turned out to be not enough, I got a 2d a year later. One for 2 Interstates and tools, the other for lawn equipment.)
Mine arrived partially assembled and finished on site.
They usually sit on 4 X 4" timber skids, and I didn't want the door so high (ramp) I couldn't easily push bikes in and out, so I dug 3 trenches for my skids and laid solid 4" cement blocks in each for the skids to rest on (with a lot of leveling). I ended up with just under 2" above grade doorway, so I needed no ramps, but water wouldn't run in either. This also kept my skids from rotting out over time and 30 years later, both are rock solid. I also ordered double 3/4" marine grade plywood floors.
Both took a lot of caulk and paint for weather/bug/mouse tight.
I trenched for a 110 electric circuit from my breaker box to the bottom of my back yard, then wired both for lights and outlets and an overhead fan.
The roofs in both was the weak link with really cheap ass shingle and no tar paper or underlayment at all. By the time each had to be replaced (with some plywood sheeting too), it cost more than the sheds did.
Choose your location wisely regarding grade (water) and shade and distance to power. And I had to beware of county code setoff in an urban neighborhood (36"). Shed height was also limited by code. My neighborhood is full of non code compliant backyard sheds; The county doesn't come around inspecting on its own, but if you get a neighbor complaint they will and then ruthless enforcement follows.
My only other advice is shed size. It's nice to be able to center the bike inside, up on the jack, and be able to work on both sides of it easily. A 10 X 12 does that nicely but a 8 X 12 may not, and the cost of the larger shed may be worth it. Floor space is limited so storage is UP not out.
I've got more, but I'll stop now.
