It seems to be taking forever for the garden to get going this year! We finally started harvesting lettuce a couple of weeks ago. When picking lettuce, don't actually pick it - use a knife to cut if off close to the ground. It will continue growing and you can keep cutting it this way until the temperatures get too hot and it goes to seed. Here in the Boise area, you can actually plant lettuce twice in each season. Plant it in early March and then again in August so you can harvest until the frost comes. You really don't need to plant much or else you will have an overabundance of lettuce.
You can see how I cut the leaves off instead of waiting for it to grow into an entire head of lettuce.
A lettuce spinner is important when washing garden lettuce. You really need to wash the individual pieces to be sure you've got it clean. This makes for a lot of water on your leaves so the spinner helps take care of that.
Chill in the fridge to crisp it up. Store in a plastic bag in the fridge for 1-2 weeks while you are waiting for more to grow.
Be sure to get as much air out as possible for longer storage.