Semi Bluff
In a tight-aggressive game the semi-bluff is a valuable tool that can be the basis for the majority of your winnings. First, let's give an example of a Semi-Bluff.
Suppose you hold
  |
| Your Hole Cards |
You call a bet on the flop, and the turn comes
   |
 |
|
| Flop | Turn |
In a tighter game, you could raise here, partially from the strength of your draws (nut flush, gutshot straight, and two overcards) partially because of the possibility that you will win the pot right here. In fact this hand is so strong that you may want to play it passively in a very-multiway pot if you have good reason to believe that others will drive the action for you. The last thing you want is to have the person to your left re-raise your bet and actually force several of your customers out!
Semi-Bluff? We don't need no stinkin' semibluff here.
The key feature of a semi-bluff is the ability to sometimes win the pot immediately from your bet. The most common scenario for a semi-bluff in a tighter game are turn raises and check-raises with draws. You hope your opponent will fold, but if they don't fold then at least you have some outs to win on the river.
The problem in a low limit game is this: You are almost NEVER going to win the pot right there. Since the semi-bluff requires that possibility it is almost never worth semi-bluffing in a low limit game unless you are doing so for deception purposes to increase the action on the river if you make your hand. In the above example, believe me that the jacks, the tens, the fours, The straight draws, the gutshot straight draws, the flush draws and any two overcards are going to call your raise.
However, in this example, you will make money by getting as much money into the pot as you can with this hand if you have more than a couple opponents on the turn. (see our percentage chart of outs with one card to come) In this case you have 9 flush outs, 3 straight outs (which don't make a flush) which is 12 outs to the absolute nuts. In addition you have two overcards which is 6 more outs of which you can probably win with 2 or 3 of them, so conservatively you have 14 outs to win. From the chart you can see that with 14 outs you have a slightly better than 30% chance to make one of your draws on the river.
As far as getting money into the pot -- you have to use your judgment to determine how best to do this. Sometimes betting is the right move while sometimes other players will do the betting (and raising for you). If you are given a choice always let the other players lead the betting because it gives you more options (in some cases to get out of the hand, to just call, or to checkraise).
While you are almost definitely beaten on the flop, you will still make money if you get more than a few callers (which you usually will). A key reason this is so is you are drawing to the nuts, so you can drive the action in the handeven if someone raises you can re-raise in this situation and still make money.
The important distinction in betting a draw in low-limit hold 'em is to do it because you are making money, not to semi-bluff