I've brewed quite a few light English ales between the 1.035 to 1.038 range, usually Bitters. From my experience there are a few key elements to these beers. Because you can't hide behind loads of malt and hops these beers are quite tricky to make.
1. Malt choice.
Use the best quality and freshest Pale malt you can get. In the past I've used floor malted Mariss Otter, but I reckon the traditonal ale malt by IMC would also be good and fresher . These malts have an EBC around 5, and have good depth of flavour. I've tried adding other malts like Munich, but think they can be too much for this style. I now only use Pale and crystal.
You'll need the addition of some specialty grains otherwise the beer will seem a bit lacking. I've played around with using crystal and small additions of chocolate, but have found CaraAroma does a very good job. The CaraAroma adds just the slightest hint of roastiness, nothing out of style. My standard practice is to use 50/50 medium crystal (Thomas Fawcett) and CaraAroma. I use 2.5% of each for a total addition of 5%.
Don't use any adjuncts like sugars or torrefied wheat. These add little to nothing in terms of flavour, and with low OG's you need all malt. Don't worry about using wheat for head retention, these beers are not known for a big lacey head.
2. Hops Choice
The key here is to use the best quality you can. IMHO you can't go past Golding and Fuggle. Don't use a high alpha hops for bittering. Any harshness will come through and can't be masked by loads of malt. The more noble hops will give a much better flavour profile even for bittering. From experience I now add the bittering at 60mins, and flavour at 15mins and flame out.
Keep the IBU's fairly low. Too highly bittered will through the balance right out. I aim to have an IBU:GU ratio of about 0.6 to 0.65. So for a 1.038 beer this would be about 23-25 IBUs. And also don't go OTT on the flavour additions, because a heavy handed approach will also through out the balance
3. Yeast Choice
Again you are looking to add as muh flavour as possible, so neutral yeast are out (IMHO). My personal favourites for this style are Wyeast 1028 and then 1968. Ferment at the top end of their range to get a nice ester profile.
Light beers are bloody hard to get right. With a low OG you have to work hard to get as much flavour into your beer as possible without sacrificing balance. These beers are a good challenge and great to drink, particularly if you want more than 1 or 2 or 3 or 4..........