Check out http://www.dotabuff.com/heroes/techies/builds . Stasis trap should be taken last, anything else decreases win rate. Suicide level 2,3 is very strong if you didn't manage to use it on level 2. You want it maxed the entire time until you actually find a kill using it. Then after that you level around your cooldown but still want it maxed for kills. Techies has no other offensive skill than suicide. The rest is just push/anti push skills until you have a lot of mana items. (Land mine works if you have setup or the enemy is stupid to stay near creeps after you place it. Ulti mine you might get 1 off in a team fight, doing half damage of suicide.)
Having stasis trap levelled early also increases the chance you will place them, meaning you wasted mana you don't have unless you have a KOTL on your team.