Here are a quick couple tips that ive picked up on and many other probably know these too.

1) Think of the river as 0 Ave, the street numbers get bigger from there. The same with Burnside, it separates N and S.

2) Going North from Ankeny till like Thurman the streets are alphabetical.

3) Numbers start from 0 and move out, so if your address was like 1950 SE Ankeny you would ride Ankey until SE 19th.
Now if your address was 1500 NE 20th, you'd go to 20th and then go 15 blocks North of Burnside.

4) One side of the block has number, the other evens.

There are lot of little intricacies to a city, this is by no means a bible.

imagine the whole city as a grid. the willamette is the x datum and burnside is the Y datum. anything with an E for east is on the east side of the river. anything with a W for west is on the West side. Anything with an N for north is north of Burnside street. Anything with an S for south is, of course, south of burnside street. For N-S running streets many are numbered 1st, 2nd, 3rd etc.. that gets tricky because there are often 2 or more numbers streets with the same number and the only designator to separate them will be Avenue, Street, Way or Place. Why? i dunno. I do know that numbering streets like this is a very old (like 1000's of years) tekneek.
Many of the closer in (portland city proper) streets are alphabetical ( ash, burnside, couch, davis, everett, flanders etc..) but this is only for *some* streets running E-W, as they (the city planners) seem to add streets here and there at whimsy. This also only applies to streets North of burnside not including ash or ankeny depending on where you are. South of burnside street, they are named after trees, then presidents, then ? It's easier to find your way around PDX than SF, and SF is only 49 sq miles (7x7)

but then theres Ladds Addition which is onna whole different type of shit...like Amsterdam...

Portland grid system and numbers are actually based on a system used in Philadelphia. In the thirties, the WPA paid crews to go around town renumbering and renaming streets to get where we are now. Those little ceramic numbers you see on houses usually come from that era.

/non sequiter

The deal with alphabetical streets is this: in NW Portland, they go in a perfect alphabet pretty much until Vaughn, the A starts in SW at Ankeny, then Burnside, Couch, Davis, Everett, Flanders, Glisan, Hoyt, Irving, etc. In NE, this is not the case at all really. For example, I live on Irving, but Glisan is only a block away and Hoyt gets skipped - yet if you go down a couple blocks, Hoyt is there seperating Irving from Glisan.

Knowing all of this stuff like what was said above is far more valuable than just pulling out a map everytime, because in a race you can quickly route things in your head without getting out a pen and map, even if your memory isn't totally photographic.