General advice I can give you is to avoid advantageous areas which you can only access from 1 or 2 small entry points. Such chokepoints might seem tactically interesting, but it usually deranges into a camp/ranged fest. Providing plenty of flanking options keeps the battle moving and prevents drawn out rounds. If you have important tactical locations though, make sure both teams take about the same time to get to there from spawn, for the sake of balance.
(Not really a veteran mapmaker myself, but I have a good idea of how battle works)
For your map specifically I'd say it could become a bit of a rangedfest, but that is just how towers work. You have multiple entry ways to both of them so I guess that is okay. Spawn 1 maybe needs an easier entry to the high part, seeing as Spawn 2 has a plain staircase. I would also create spots from the scaffolding to get over the battlements without jumping, as jumping leaves you vulnerable and makes entry slow. You have done this the other way, but you could do it both ways with some small objects. Maybe add a bit of broken battlement so they can get in there more easily. Of course both teams should be able to get onto the high part at about the same time into the round. Also keep in mind that cavalry might be able to run up the stairway, giving Spawn 2 easier cav access than 1.
Visually you might want to seperate the very high wall into 2 walls stacked on top of eachother, because it looks a bit stretched this way.
Edit: oops, thought there was only the one screen.
