Just a quick and very effective build please try it

simple again flat armor and magic res. for early durability and magic penetration for the deadly poison

basic tank masteries with a point in utility mastery for that most important blue buff time extention

start with poison or fling i prefer poison in solo lane and fling in 2vs2 starts. i dont pick my skill until i saw who am i against in the lane no need to hurry on that! take a W at lvl 4 and R==> Q==> E==> W is ur priority sequence after that

i go teleport and ghost. depending on ur team mates u can use really anything on singed. flash and fling can be fun, exaust is handy chasing fasties, ignite is good against heavy ad's with life steals. after that is really not very compatible with singed...

Singed is a great farmer and team destroyer char if it was used in right way, u can become a fear in battle field with ur poison use it to the advantage of ur team not urs... fling will save many team mates but if you fling them wrong way u may be ***iting enemy tem so carefull on that. watch ur mana if you dont have blue buff forgetting the taps on will cause quick mana starvation. introduce a mana regen item if you like. ur key item in this build is Force of nature it will keep u alive, extend ur lane durability and give u that little extra speed u really need. this should be ur 3rd item to complete. try to put together rod of ages first as it gives u bonus stats in time than ur boots which will nearly double ur poison penetration. 3rd FN as we said Than get some hp or armor depending the games direction and build ur sunfire cape 4th. after that ur last items are very flexy take a moment to look at the score board. who is doing well in the other team and counter them with ur items. i go for banshees veil and guardian angel usually but i can end up with another FN or thornmail depending who is fed :) Good luck and Please play and post a Feed back/ Thank you