Two main pieces of advice:
First, make sure your home is competitively priced. Guy's second point, below, specifically addresses how to do this.
Second, make sure your home shows well. That means not only in person, but also online, with many high-quality photos. Consider having a home stager do an evaluation. It may cost a few hundred dollars, but will be well worth it. Then, after getting the house in shape, get a good photographer (not necessarily a professional, but one who knows what he/she is doing) to take photos. Then make sure they're posted on your listing.
Also, let me address a few of the concerns you raised in your question. Some are legitimate. Others, not so important.
Realtor had a open house 2 months ago but the assistant showed the house. The assistant did not no anything about the house.
Open houses seldom sell houses. Often, agents do open houses for 2 reasons: (1) To let the seller see that the agent is doing something; and (2) To get leads for possible clients--the ones who come in and look at the open house rarely buy that house, but they're often in the market. So 1 open house 2 months ago isn't a terrible problem. And while it'd be preferable for the agent to show the house, busy agents often have multiple open houses on the same day so they'll have someone else fill in.
However, it's not acceptable that the person showing the house didn't know anything about it. Whoever is showing the house should be prepared with the answers to all reasonable questions, and--more than that--should be actively "selling"--promoting the good points of the property.
I am seeing SOLD and SALE PENDING all over our neighborhood and the homes are similar in price and bedrooms, square footage etc. I am very frustrated.
If the houses that are selling are comparable, that's a concern. Earlier, I mentioned that price and appearance are the two main factors in selling a property. Marketing is also important, but sometimes is overrated by sellers. Lots of people search online, so a lot of marketing just means making sure your home is on the MLS (with lots of good pictures) and a good write-up or description. There are other things agents can do to market homes--everything from holding broker's opens (your agent should do that) to direct mail to neighbors reminding them of a house for sale in their community, and so on. So, don't overlook marketing, but make sure that the other two legs of the tripod--price and appearance--are taken care of.
I understand the market is very slow and things are not selling like they used to be but 0 showing in the last month!!! Prime selling time is going to pass and I believe there is very little effort from the Realtor.
Don't be worried about whether your agent is doing the showings. In most cases, the showings will be done by other agents representing buyers. The real question, then, isn't about the number of showings by YOUR agent, but the TOTAL number of showings by all agents. And here it depends on market conditions. But if your home is properly priced, is attractive, and is marketed properly, in many areas of the country you should be getting 2-5 showings a week. If you haven't had any showings at all in a month (or since you listed 3 months ago), then something is seriously wrong. Especially if similar properties are selling.
Final piece of advice: Set up a meeting with your agent. Discuss these issues. Get a new, current CMA. Do what Guy suggests. Check out your listing online and see how it compares (the write-up, the photos, etc.) with other listings. Ask your agent what marketing activities he/she has been doing. And ask specifically: "What do we have to do to get an offer on our property in the next 30 days?" And while I've said several times that price is very, very important, some agents tend to be a bit, ummm, lazy and just go for the price cut when other factors--such as staging or curb appeal--may be the real problem.
Hope that helps.